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181.
In a companion paper two different modelling approaches have been described, operating at the meso‐scale of the fibre elements and at the micro‐scale of the finite element (FE) method. The aim of this paper is to explore the efficiency of these models in the pushover analysis for the seismic assessment of existing reinforced concrete (RC) structures. To this purpose a prototype reference structure, one of the RC shear walls designed according to the multi‐fuse concept and tested on shaking table for the CAMUS Project, is modelled at different levels of refinement. At the micro‐scale the reinforcement and anchorage details are described with increasing accuracy in separate models, whereas at the meso‐scale one single model is used, where each element represents a large part of the structure. Static incremental non‐linear analyses are performed with both models to derive a capacity curve enveloping the experimental results and to reproduce the damage pattern at the displacement level where failure is reached. The comparison between experimental and numerical results points out the strong and weak points of the different models inside the procedure adopted, and the utility of an integration of results from both approaches. This study confirms, even for the rather difficult case at study, the capability of the pushover in reproducing the non‐linear dynamic response, both at a global and a local level, and opens the way to the use of the models within a displacement‐based design and assessment procedure. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
182.
Bo. R. Larsen Dario Di Bella Marianne Glasius Richard Winterhalter Niels R. Jensen Jens Hjorth 《Journal of Atmospheric Chemistry》2001,38(3):231-276
Smog chamber experiments have beenconducted in which cyclic monoterpenes were oxidisedin the gas phase by OH. The evolved secondary organicaerosol (SOA) was analysed by LC-MSn and thegas-phase products were analysed by FT-IR. Theconcentrations of the identified compoundscorresponded to carbon mass balances in the range of40%–90%. The identified compounds in the particularphase corresponded to 0.5%–4.2% of the reactedcarbon. The most abundant compounds in SOA fromterpenes with an endocyclic C=C double bond wereC10-keto-aldehydes, C10-keto-carboxylicacids, C10-hydroxy-keto-carboxylic acids, andC10-hydroxy-keto-aldehydes (pinonaldehyde,pinonic acid, hydroxy-pinonic acid isomers, andhydroxy-pinonaldehyde isomers from -pinene;3-caronaldehyde, 3-caronic acid, hydroxy-3-caronicacid isomers, and hydroxy-3-caronaldehyde isomers from3-carene). The most abundant compounds in SOA fromterpenes with an exocyclic C=C double bond wereC9-ketones, C9-dicarboxylic acids, andC10-hydroxy-keto-carboxylic acids (nopinone,pinic acid, and hydroxy-pinonic acid isomers from-pinene; sabinaketone, sabinic acid andhydroxy-sabinonic acid isomers from sabinene).Decarboxylated analogues of most of the compounds werepresent in SOA in minor concentrations, such asC9-keto-carboxylic acids (norpinonic acid,nor-3-caronic acid) and C8-dicarboxylic acids(norpinic acid, nor-3-caric acid, norsabinic acid). InSOA from limonene, which contains an endocyclic aswell as an exocyclic C=C double bond, the mostabundant compounds were a C10-keto-aldehyde andits oxo-derivative (limononaldehyde and keto-limononaldehyde) together with hydroxy-derivatives of aC10-keto-carboxylic acid (isomers ofhydroxy-limononic acid). Also aC10-keto-carboxylic acid (limononic acid) waspresent together with minor concentrations of aC9-dicarboxylic acids (limonic acid), itsoxo-derivative (keto-limonic acid), and itsdecarboxylated analogue (norlimonic acid). Mechanisticpathways for the formation of these products, some ofwhich are identified here for the first time, areproposed. 相似文献
183.
A discrete model to represent the unbounded soil (halfspace) in a soil–structure interaction analysis in the time domain is developed. For each dynamic degree of freedom of the foundation node, the discrete model consists of a mass M0 which is attached to a rigid support with a spring K and with a damper C0. In addition, a free node with the mass M1 is introduced, which is connected to the foundation node with a damper C1. All coefficients are frequency-independent. The discrete model is semi-empirical. It is based on a semi-infinite truncated cone, whereby, after enforcing the static stiffness, the remaining parameters are modified to achieve an optimal fit of the dynamic-stiffness coefficient in the frequency domain. The spring K is equal to the static stiffness. The coefficients appearing in the equations for the dampers C0, C1 and the masses M0, M1 are specified (assuming a homogeneous halfspace) for the disc, the embedded cylinder, the rectangle (also embedded) and the strip. A square on a layer whose stiffness increases with depth resting on a homogeneous halfspace is also treated. For an embedded foundation, eccentricities arise. Material damping increases the damper C0 and the mass M0. 相似文献
184.
Camuffo Dario della Valle Antonio Becherini Francesca 《Theoretical and Applied Climatology》2018,132(3-4):1143-1151
Theoretical and Applied Climatology - Surface wetness is a synergistic factor to determine atmospheric corrosion, monument weathering, mould growth, sick buildings, etc. However, its detection and... 相似文献
185.
Raffaella De Luca Domenico Miriello Alessandra Pecci Salvador Domínguez‐Bella Dario Bernal‐Casasola Daniela Cottica Andrea Bloise Gino Mirocle Crisci 《Geoarchaeology》2015,30(4):330-351
This paper presents the results of the compositional study of 29 samples of mortar from the so‐called “Garum Shop” (I, 12, 8) at Pompeii in Southern Italy. The characterization of the samples yielded information on the raw materials used in the mixtures, the production technology of mortars, and the building phases. It was carried out through polarized optical microscopy, X‐ray powder diffraction, X‐ray fluorescence, microanalysis energy‐dispersive X‐ray spectroscopic microanalysis, and image analysis through the JMicroVision software. The resultant data show great compositional homogeneity among the samples, suggesting the presence of a principal construction phase, probably associated with the first phase of the house. Apart from this main construction phase, there are some samples that show differences related either to their different function or to the fact that they come from different construction phases or restoration works. The raw materials used are related to the geology of the area and are fully compatible with the pyroclastic deposits of Vesuvius. 相似文献
186.
In 1830, Libri announced the finding of a 16-year-long record of daily temperature observed in Florence, Italy, by Father Renieri before the activity of the Medici Network (1654 to 1670) that is usually considered the earliest instrumental series in the world. The Libri announcement was supported by the concurrent finding of a box with the early Little Florentine Thermometers that survived the Inquisition and was confirmed by Schouw, von Humboldt and Maxwell. However, all investigations made to find Renieri’s observations were fruitless. This paper clarifies this complex situation differentiating between myth and reality. A careful analysis of the Libri’s announcement in the historical context points out that Libri made the announcement while escaping for conspiracy from Florence and needed a scoop to be introduced in the French Academy of Sciences. For this reason he made a deliberate mix of new and old assertions, i.e. he claimed to have made new discoveries but without explaining too much and reporting misleading details about well known stories concerning the earliest meteorological observations. This induced people to suppose that further, earlier records existed. The consequence of this was that climatologists searched for years the claimed records. This paper shows that the Medici Network almost certainly contains the earliest exploitable instrumental observations. The possibility of finding a short series of observations prior to 1654 is remote. 相似文献
187.
Autogenic dynamics of alluvial fans in endorheic basins: Outcrop examples and stratigraphic significance 总被引:1,自引:0,他引:1
Alluvial fans are relatively simple depositional systems, due to the direct coupling of sediment sources and adjacent accumulation areas. Nonetheless, general models of alluvial‐fan evolution and stratigraphy remain elusive, due to the great sensitivity of such systems to allogenic controls and their strongly case‐specific responses. Autogenic processes intrinsic to alluvial‐fan dynamics can complicate stratigraphic architectures, with effects not easily distinguishable from those of allogenic forcing. A distinction is made here between lateral autogenic dynamics, tied to spatial sediment distribution over fan surfaces, and vertical autogenic dynamics, related to independent incision‐aggradation cycles. Autogenic mechanisms have been highlighted recently by modelling studies, but remain poorly constrained in field‐based studies. Examples are presented here from the margins of the Cenozoic Teruel and Ebro basins (Spain), where alluvial fans accumulated thick successions during phases of basin topographic closure and endorheic drainage which promoted forced aggradation. Fan successions consist of conformable architectures of stacked clastic sheets, laterally continuous and with no evidence of internal unconformities, inset architectures, fan segmentation or preserved incised channels. Continuous aggradation in these closed basins strongly inhibited ‘vertical’ autogenic dynamics in the form of fan head and through fan incision, due to the forced rise in geomorphic base level and the creation of positive accommodation. Furthermore, the lack of incised channels favoured widespread sediment transport and aggradation over broad fan sectors in relatively short time spans, in contrast to the typical occurrence of active lobes and abandoned fan surfaces caused by ‘lateral’ autogenic dynamics. Stratigraphic records of alluvial fans developed in endorheic basins are essentially complete and largely unaffected by autogenic processes. The latter characteristic implies that they can be more unambiguously interpreted in terms of allogenic forcing, because stratigraphic signatures are not complicated by the effects of complex fan autodynamics. 相似文献
188.
Giovanni Gullà Dario Peduto Luigi Borrelli Loredana Antronico Gianfranco Fornaro 《Landslides》2017,14(1):171-188
The geometric and kinematic characterization of landslides affecting urban areas is a challenging goal that is routinely pursued via geological/geomorphological method and monitoring of ground displacements achieved by geotechnical and, more recently, advanced differential interferometric synthetic aperture radar (A-DInSAR) data. Although the integration of all the above-mentioned methods should be planned a priori to be more effective, datasets resulting from the independent use of these different methods are commonly available, thus making crucial the need for their standardized a posteriori integration. In this regard, the present paper aims to provide a contribution by introducing a procedure that, taking into account the specific limits of geological/geomorphological analyses and deep/surface ground displacement monitoring via geotechnical and A-DInSAR data, allows the a posteriori integration of the results by exploiting their complementarity for landslide characterization. The approach was tested in the urban area of Lungro village (Calabria region, southern Italy), which is characterized by complex geological/geomorphological settings, widespread landslides and peculiar urban fabric. In spite of the different level of information preliminarily available for each landslide as result of the independent use of the three methods, the implementation of the proposed procedure allowed a better understanding and typifying of the geometry and kinematics of 50 landslides. This provided part of the essential background for geotechnical landslide models to be used for slope stability analysis within landslide risk mitigation strategies. 相似文献