全文获取类型
收费全文 | 70篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 4篇 |
地球物理 | 19篇 |
地质学 | 18篇 |
海洋学 | 7篇 |
天文学 | 14篇 |
综合类 | 1篇 |
自然地理 | 5篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
1950年 | 1篇 |
1947年 | 1篇 |
1946年 | 2篇 |
1945年 | 1篇 |
1944年 | 2篇 |
排序方式: 共有71条查询结果,搜索用时 15 毫秒
1.
Mission and hardware constraints make the Cassini radar altimeter working in the beam limited or pulse limited mode dependent on the radar operative mode (Low and High Resolution, respectively), but never allows work in a condition such that the pulsewidth limited circle is much smaller than the beamwidth limited circle. Unfortunately this latter condition is vital for the application of the so-called Brown model widely and successfully used in Earth (ocean) observation missions where the quoted condition is really met. In the paper a new model is discussed which is based on the same general hypotheses of the Brown model but is worked out by means of a different approach which makes it more general and independent of the specific operative conditions. An extension of the new model to take into account large mispointing angles is considered as well based on a series expansion of the Bessel function and on the analysis of the truncation error. Finally a comparison with the classical Brown model is discussed too. 相似文献
2.
Integration of on-land and offshore geomorphological and structural investigations coupled to extensive radiometric dating of co-seismically uplifted Holocene beaches allows characterization of the geometry, kinematics and seismotectonics of the Scilla Fault, which borders the eastern side of the Messina Strait in Calabria, Southern Italy. This region has been struck by destructive historical earthquakes, but knowledge of geologically-based source parameters for active faults is relatively poor, particularly for those running mostly offshore, as the Scilla Fault does. The 30 km-long normal fault may be divided into three segments of 10 km individual length, with the central and southern segments split in at least two strands. The central and northern segments are submerged, and in this area marine geophysical data indicate a youthful morphology and locally evidence for active faulting. The on-land strand of the western segment displaces marine terraces of the last interglacial (124 to 83 ka), but seismic reflection profiles suggest a full Quaternary activity. Structural data collected on bedrock faults exposed along the on-land segment provide evidence for normal slip and NW-SE extension, which is consistent with focal mechanisms of large earthquakes and GPS velocity fields in the region. Detailed mapping of raised Holocene marine deposits exposed at the coastline straddling of the northern and central segments supplies evidence for two co-seismic displacements at 1.9 and 3.5 ka, and a possible previous event at 5 ka. Co-seismic displacements show a consistent site value and pattern of along-strike variation, suggestive of characteristic-type behaviour for the fault. The 1.5–2.0 m average co-seismic slips during these events document Me 6.9–7.0 earthquakes with 1.6–1.7 ka recurrence time. Because hanging-wall subsidence cannot be included into slip magnitude computation, these slips reflect footwall uplift, and represent minimum average estimates. The palaeoseismological record based on the palaeo-shorelines suggests that the last rupture on the Scilla Fault during the February 6, 1783 Mw = 5.9–6.3 earthquake was at the expected time but it may have not entirely released the loaded stress since the last great event at 1.9 ka. Comparison of the estimated co-seismic extension rate based on the Holocene shoreline record with available GPS velocities indicates that the Scilla Fault accounts for at least 15–20% of the contemporary geodetic extension across the Messina Strait. 相似文献
3.
Installation of a vertical slurry wall around an Italian quarry lake: complications arising and simulation of the effects on groundwater flow 总被引:1,自引:0,他引:1
Slurry walls are non-structural barriers that are constructed underground to impede groundwater flow or manage groundwater
control problems. The study area is in the Piemonte plain (Italy), close to the River Po. Quarrying works carried out below
the piezometric surface created two big quarry lakes. The local groundwater system is characterized by a lower semi-confined
aquifer, which is overlain by a semi-permeable bed of clayey peat (aquitard) and an upper unconfined aquifer. Locally, the
peat fades away and the granulometry of this horizon becomes silty sandy. A planned enlargement of the quarry will increase
the size and depth of the quarry lakes. So the aquitard bed between the two aquifers will be damaged, creating a mixing rate
of groundwater. Such a procedure would not be compatible with the presence of two municipal wells upstream from the quarries.
Consequently, the installation of a vertical diaphragm (slurry wall) is recommended to separate the aquifers and to act as
a filter for the groundwater flowing from the unconfined to the semi-confined aquifer. To predict the consequences caused
by the installation of the vertical diaphragm separating the unconfined aquifer and the semi-confined one, a specifically
adjusted finite-difference model was used. The model showed a maximum rising of the water table equal to 12 cm, just upstream
of the diaphragm and for a distance of about 100 m, and a maximum lowering of 2 cm just downstream of the diaphragm. However,
the slurry wall would not cause any change in the piezometric head in the area where there are municipal wells and, hence,
will not have any negative effect on the functionality of the municipal wells. Moreover, the migration of water from the unconfined
aquifer through the vertical diaphragm will stimulate a series of attenuation and auto-depuration processes of eventual contaminants.
These processes are due to the higher crossing time that the groundwater flow takes to go through the vertical barrier (t
a = 96.5 days, whereas for the horizontal semi-permeable layer t
a = 9.6 days). So, the vertical diaphragm can be a resolutive element, representing a mediation and separation factor between
the unconfined and the semi-confined aquifers along the border of the quarrying areas, and a protective barrier for the water
quality of the quarry lake and the semi-confined aquifer. 相似文献
4.
Ennio Badolati 《Earth, Moon, and Planets》1982,26(3):339-341
In this paper it is remarked that the so called Basano-Hughes law of planetary distances coincides with a formula suggested by G. Armellini in 1921. Besides some additional remarks are made on the laws of planetary distances.
Riassunto In quest' articolo viene mostrato che la cosiddetta legge di Basano-Hughes sulle distanze planetarie coincide con la formula di G. Armellini (1921). Inoltre vengono fatte alcune considerazioni sulle leggi relative alle distanze planetarie.相似文献
5.
Summary ¶This study presents a numerical simulation of the bora wind as it occurs in form of a severe wind blowing down coastal mountains and over the Adriatic Sea. A typical cyclonic bora event, occurring during the period January 3–6, 1995, is simulated using a nested limited area model. An integration, with horizontal resolution of about 14km, and a nested one, with higher resolution, about 5.5km, are presented. The 1997 version of the Eta Model is used for both the lower resolution and the higher resolution runs. Numerous details of the simulation are found to be in good agreement with the understanding as well as the observational knowledge of the bora, thus supporting confidence in the realism of the results. In particular, features of the simulated flow are seen strongly indicative of some basic characteristics of the hydraulic model of the phenomenon, such as the mountain wave breaking and the upstream flow acceleration. Moreover, the increase in horizontal resolution, in combination with an improvement of the coastal SST information, led to a still improved realism of the low-level wind representation over the Adriatic Sea.Received December 31, 2001; revised March 25, 2002; accepted July 19, 2002
Published online: February 20, 2003 相似文献
6.
A structural and geophysical approach to the study of fractured aquifers in the Scansano-Magliano in Toscana Ridge, southern Tuscany, Italy 总被引:1,自引:0,他引:1
Roberto Francese Francesco Mazzarini Andrea Bistacchi Gianfranco Morelli Giorgio Pasquarè Nicola Praticelli Henry Robain Nigel Wardell Annalisa Zaja 《Hydrogeology Journal》2009,17(5):1233-1246
Fresh water availability has recently become a serious concern in the Italian Apennines, as various activities rely on a predictable supply. Along the ridge between Scansano and Magliano in Toscana, in southern Tuscany, the situation is further complicated by contamination of the nearby alluvial aquifers. Aquifers locally consist of thin fractured reservoirs, generally within low-permeability formations, and it can be difficult to plan the exploitation of resources based on conventional techniques. An integrated study based on geological data investigated the link between tectonics and groundwater circulation, to better define the hydrological model. After the regional identification of fault and fracture patterns, a major structure was investigated in detail to accurately map its spatial position and to understand the geometry and properties of the associated aquifer and assess its exploitation potential. The subsurface around the fault zone was clearly imaged using ground probing radar, two-dimensional and three-dimensional resistivity tomography, and three-dimensional shallow seismic surveys. The vertical and horizontal contacts between the different geological units of the Ligurian and Tuscan series were resolved with a high degree of spatial accuracy. Three-dimensional high-resolution geophysical imaging proved to be a very effective means of characterising small-scale fractured reservoirs. 相似文献
7.
Enrico Costa Ronaldo Bellazzini Gianpiero Tagliaferri Giorgio Matt Andrea Argan Primo Attinà Luca Baldini Stefano Basso Alessandro Brez Oberto Citterio Sergio Di Cosimo Vincenzo Cotroneo Sergio Fabiani Marco Feroci Antonella Ferri Luca Latronico Francesco Lazzarotto Massimo Minuti Ennio Morelli Fabio Muleri Lucio Nicolini Giovanni Pareschi Giuseppe Di Persio Michele Pinchera Massimiliano Razzano Luigia Reboa Alda Rubini Antonio Maria Salonico Carmelo Sgro’ Paolo Soffitta Gloria Spandre Daniele Spiga Alessio Trois 《Experimental Astronomy》2010,28(2-3):137-183
Since the birth of X-ray astronomy, spectral, spatial and timing observation improved dramatically, procuring a wealth of information on the majority of the classes of the celestial sources. Polarimetry, instead, remained basically unprobed. X-ray polarimetry promises to provide additional information procuring two new observable quantities, the degree and the angle of polarization. Polarization from celestial X-ray sources may derive from emission mechanisms themselves such as cyclotron, synchrotron and non-thermal bremsstrahlung, from scattering in aspheric accreting plasmas, such as disks, blobs and columns and from the presence of extreme magnetic field by means of vacuum polarization and birefringence. Matter in strong gravity fields and Quantum Gravity effects can be studied by X-ray polarimetry, too. POLARIX is a mission dedicated to X-ray polarimetry. It exploits the polarimetric response of a Gas Pixel Detector, combined with position sensitivity, that, at the focus of a telescope, results in a huge increase of sensitivity. The heart of the detector is an Application-Specific Integrated Circuit (ASIC) chip with 105,600 pixels each one containing a full complete electronic chain to image the track produced by the photoelectron. Three Gas Pixel Detectors are coupled with three X-ray optics which are the heritage of JET-X mission. A filter wheel hosting calibration sources unpolarized and polarized is dedicated to each detector for periodic on-ground and in-flight calibration. POLARIX will measure time resolved X-ray polarization with an angular resolution of about 20 arcsec in a field of view of 15 × 15 arcmin and with an energy resolution of 20% at 6 keV. The Minimum Detectable Polarization is 12% for a source having a flux of 1 mCrab and 105 s of observing time. The satellite will be placed in an equatorial orbit of 505 km of altitude by a Vega launcher. The telemetry down-link station will be Malindi. The pointing of POLARIX satellite will be gyroless and it will perform a double pointing during the earth occultation of one source, so maximizing the scientific return. POLARIX data are for 75% open to the community while 25% + SVP (Science Verification Phase, 1 month of operation) is dedicated to a core program activity open to the contribution of associated scientists. The planned duration of the mission is one year plus three months of commissioning and SVP, suitable to perform most of the basic science within the reach of this instrument. A nice to have idea is to use the same existing mandrels to build two additional telescopes of iridium with carbon coating plus two more detectors. The effective area in this case would be almost doubled. 相似文献
8.
The catalog of the meteorite collection of the Italian Museum of Planetary Sciences in Prato (Italy)
Marco Morelli Annarita Franza Daniela Faggi Giovanni Pratesi 《Meteoritics & planetary science》2023,58(7):945-954
For the first time, this paper presents to the planetary scientists' community the catalog of the meteorite collection preserved at the Italian Museum of Planetary Sciences (Museo Italiano di Scienze Planetarie, henceforth MISP) in Prato (Italy). Founded in 2005, MISP is a type specimen official repository approved by the Nomenclature Committee of the Meteoritical Society. It represents one of the few museums worldwide entirely devoted to planetary sciences. The catalog of its meteorite collection encompasses 430 meteorites for a total of 1536 specimens, including 291 thin sections, 184 thick sections, and 278 specimens that MISP has classified. Furthermore, MISP is currently classifying 57 other meteorites. Some samples were found during meteorite recovery expeditions in hot deserts, promoted by MISP in collaboration with diverse Italian universities and national research institutions. MISP also keeps an impact rocks collection comprising 257 samples. In a country like Italy, where most of the collected meteorites are housed in museums whose catalogs are not available online, the publication of the MISP meteorite collection catalog, together with the catalog of the impact rocks collection, represents not only a significant scientific primary source but also a remarkable tool for disseminating meteoritics to nonresearch audiences in educational activities and citizen science projects. 相似文献
9.
Christian Circi Ennio Condoleo Emiliano Ortore 《Celestial Mechanics and Dynamical Astronomy》2017,128(2-3):361-382
Taking into consideration a probe moving in an elliptical orbit around a celestial body, the possibility of determining conditions which lead to constant values on average of all the orbit elements has been investigated here, considering the influence of the planetary oblateness and the long-term effects deriving from the attraction of several perturbing bodies. To this end, three equations describing the variation of orbit eccentricity, apsidal line and angular momentum unit vector have been first retrieved, starting from a vectorial expression of the Lagrange planetary equations and considering for the third-body perturbation the gravity-gradient approximation, and then exploited to demonstrate the feasibility of achieving the above-mentioned goal. The study has led to the determination of two families of solutions at constant mean orbit elements, both characterised by a co-planarity condition between the eccentricity vector, the angular momentum and a vector resulting from the combination of the orbital poles of the perturbing bodies. As a practical case, the problem of a probe orbiting the Moon has been faced, taking into account the temporal evolution of the perturbing poles of the Sun and Earth, and frozen solutions at argument of pericentre 0\(^{\circ }\) or 180\(^{\circ }\) have been found. 相似文献
10.
Kondratenko Aleksei Kanyilmaz Alper Castiglioni Carlo Andrea Morelli Francesco Kohrangi Mohsen 《Bulletin of Earthquake Engineering》2022,20(2):1247-1295
Bulletin of Earthquake Engineering - Automated Multi-Depth Shuttle Warehouses (AMSWs) are compact storage systems that provide a large surface occupation and therefore maximum storage density.... 相似文献