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991.
Application of Multivariate Statistical Techniques for Characterization of Groundwater Quality in the Coastal Aquifer of Nador,Tipaza (Algeria) 总被引:1,自引:0,他引:1
Abdelkader Bouderbala Boualem Remini Abdelamir Saaed Hamoudi Antonio Pulido-Bosch 《Acta Geophysica》2016,64(3):670-693
The study focuses on the characterization of the groundwater salinity on the Nador coastal aquifer (Algeria). The groundwater quality has undergone serious deterioration due to overexploitation. Groundwater samplings were carried out in high and low waters in 2013, in order to study the evolution of groundwater hydrochemistry from the recharge to the coastal area. Different kinds of statistical analysis were made in order to identify the main hydrogeochemical processes occurring in the aquifer and to discriminate between different groups of groundwater. These statistical methods provide a better understanding of the aquifer hydrochem-istry, and put in evidence a hydrochemical classification of wells, showing that the area with higher salinity is located close to the coast, in the first two kilometers, where the salinity gradually increases as one approaches the seaside and suggests the groundwater salinization by sea-water intrusion. 相似文献
992.
Laura Carrillo Emilio Palacios-Hernández Mario Yescas Ana María Ramírez-Manguilar 《Estuaries and Coasts》2009,32(5):906-916
Salinity profiles and meteorological data were analyzed during February, May, and September 2006 in Chetumal Bay, a large,
shallow estuary of the Western Caribbean. Local meteorological conditions revealed three seasons: (1) a dry season (March–May);
(2) a wet season (June–October); and (3) the nortes season, with northerly wind events (October–February). During the nortes
and wet seasons, salinity ranged between 13 and 16 psu, and salinity was highest in the dry season, ranging between 18 and
22 psu over most of the area; a strong stratification and a significant contribution of salty water characterized this season.
Strong horizontal gradients were observed near Rio Hondo during the three seasons. Deep and narrow peculiar bathymetric features
called the pozas showed a strong stratification and a relatively high salinity. The northern part of Chetumal Bay and probably
the entire system are far from being homogeneous. 相似文献
993.
Carlos M. Duarte Daniel J. Conley Jacob Carstensen María Sánchez-Camacho 《Estuaries and Coasts》2009,32(1):29-36
The implicit assumption of many scientific and regulatory frameworks that ecosystems impacted by human pressures may be reverted
to their original condition by suppressing the pressure was tested using coastal eutrophication. The response to nutrient
abatement of four thoroughly studied coastal ecosystems that received increased nutrient inputs between the 1970s and the
1980s showed that the trajectories of these ecosystems were not directly reversible. All four ecosystems displayed convoluted
trajectories that failed to return to the reference status upon nutrient reduction. This failure is proposed to result from
the broad changes in environmental conditions, all affecting ecosystem dynamics, that occurred over the 30 years spanning
from the onset of eutrophication to the reduction of nutrient levels. Understanding ecosystem response to multiple shifting
baselines is essential to set reliable targets for restoration efforts. 相似文献
994.
Nabil Sultan Antonio Cattaneo Jean-Claude Sibuet Jean-Luc Schneider the Sumatra Aftershocks team 《International Journal of Earth Sciences》2009,98(4):823-837
The swath bathymetric data acquired during the “Sumatra Aftershocks” cruise from the Sunda trench in the Indian Ocean to the
north of the Sumatra Island imaged several scars and deposits. In situ pore pressure measurements using the Ifremer piezometer
and coring demonstrate that high excess pore pressure and sediment deformation was generated by a recent event in the scar
of the slope failure zone identified by J.T. Henstock and co-authors. This excess pore pressure is localized in the upper
sedimentary layers and is not related to an interplate subduction process. Numerical simulations of the hydrological system
that take into account the hydro-mechanical properties of the upper sediment layer show that the excess pore pressure and
sediment deformations could be generated at the time of the December 26, 2004 Great Sumatra Earthquake.
The Sumatra Aftershocks team: J.-C. Sibuet, S. Singh, R. Apprioual, N.C. Aryanto, J. Begot, A. Cattaneo, A.P.S. Chauchan,
R. Creach, J. Crozon, A. Domzig, N. Falleau, D. Graindorge, F. Harmegnies, Y. Haryadi, F. Klingelhoffer, S.K. Kolluru, J.-Y.
Landuré, C. Le Lann, J. Malod, A. Normand, G. Oggian, C. Rangin, D. Restunin Galih, J.-L. Schneider, N. Sultan, M. Taufik,
M. Umber and H. Yamaguchi. 相似文献
995.
Patrícia Kováčová Laurent Emmanuel Natália Hudáčková Maurice Renard 《International Journal of Earth Sciences》2009,98(5):1109-1127
Stable isotope data of the foraminiferal carbonate shells and bulk sediment samples from the Central Paratethys were investigated
to contribute to better knowledge of the paleoenvironmental changes in Badenian (Middle Miocene). Five benthic (Uvigerina semiornata, U. aculeata, Ammonia beccarii, Elphidium sp. and Heterolepa dutemplei) and three planktonic taxa (Globigerina bulloides, G. diplostoma and Globigerinoides trilobus), characterising the bottom, intermediate and superficial layers of the water column, were selected from the Vienna Basin
(W Slovakia). The foraminiferal fauna and its isotope signal point out to temperature-stratified, nutrient-rich and consequently
less-oxygenated marine water during the Middle/Late Badenian. Negative carbon isotope ratios indicate increased input of 12C-enriched organic matter to the bottom of the Vienna Basin. Positive benthic δ18O implies that the global cooling tendency recorded in the Middle Miocene has also affected the intramountain Vienna Basin.
In this time, the Central Paratethys has been in the process of isolation. Our stable isotope trend suggests that the communication
with Mediterranean Sea has been still more or less active on the south of Vienna Basin (Slovak part) in the Late Badenian,
whereas the seawater exchange towards north was apparently reduced already during the Middle Badenian. 相似文献
996.
F. J. García Navarro J. A. Amorós Ortiz-Villajos C. J. Sánchez Jiménez S. Bravo Martín-Consuegra E. Márquez Cubero Raimundo Jiménez Ballesta 《Environmental Earth Sciences》2009,59(3):603-611
The study described here involved evaluating the effects that the application of one by-product (sugar foam waste) has upon
red soils in the region of La Mancha (Central Spain). In view of the fact that this is a location where this type of soil
abounds, this technique has been a common practice for many years. The principal goal was to investigate the impact of this
approach on some of the soil properties and, secondly, on its level of fertility. As a result, this represents an investigation
into the effects that this type of waste has on some soil quality parameters. The results showed that, after the addition
of by-products over 25 years, sugar foam waste is of agricultural interest mainly due to the increase in organic matter concentration
(about 2%) and, to a lesser extent, by increases in calcium carbonate (more than 30%) and P (four times more). The soil pH
was also found to increase slightly (1.4), while the electrical conductivity almost did not change. The properties associated
with these pedological qualities therefore had a positive effect by improving nutrient availability. As a result, foams arising
from sugar industries have a positive effect on soil quality and the application of such foams to soils is beneficial since
the need to dispose this residue is also removed. 相似文献
997.
The western sector of the Tagliamento River basin (Friuli Venezia-Giulia Region; northern Italy) is characterized by important water resources, both superficial and underground. In particular, in the Quaternary deposits of the plain, up to a depth of 500 m, six artesian aquifer systems exist. A large amount of lithological, geomorphological, and hydrogeological data is presented, allowing for definition of (a) the principal aquifer system of the area to a depth of about 500 m; (b) geometrical characteristics of the aquifers (thickness, lateral extension, etc); (c) the hydraulic parameters (hydraulic conductivity, transmissivity); (d) chemico-physical characteristics of the water; and (e) vulnerability to pollution of the aquifer systems. In a test area, where many boreholes were drilled for fresh water supply, the conceptual hydrogeological model was integrated by a detailed and repeated three-dimensional (3D) resistivity survey using combined electrical resistivity tomography (ERT) and time-domain electromagnetic (TDEM) soundings. ERT investigation was mainly used to get detailed information about geometry and porosity of the overburden and to calibrate the shallowest TDEM information. 相似文献
998.
David Sanz Juan José Gómez-Alday Santiago Castaño Angel Moratalla Jorge De las Heras Pedro Emilio Martínez-Alfaro 《Hydrogeology Journal》2009,17(6):1375-1391
The Mancha Oriental System (MOS) has a surface area of 7,260 km2, making it one of the largest carbonate aquifer systems in Spain. The system sustains about 1,000 km2 of irrigated crops and supplies groundwater to 275,000 inhabitants. The economic transformation brought about by the development of extensive irrigated cropland has led to a water-balance disequilibrium of about 75 million m3/year. This input–output deficit has negative consequences in the quantity and quality of the available resources, in the river–aquifer relationship, and in the associated ecosystems as well. To understand the hydrogeological behaviour of the system, it is necessary to design a conceptual model. Further, the conceptualisation of a groundwater flow system is a requirement of the European Water Framework Directive for the characterisation of groundwater bodies. The robustness of the conceptual model depends heavily on the user capability of representing the real system. In this work, a multidisciplinary approach has been used to represent the three-dimensional geological framework and the groundwater flow conceptualisation of the MOS. Data management and three-dimensional visualisation have been carried out by means of geographical information system (GIS) tools and software for contouring and three-dimensional surface mapping. 相似文献
999.
Kryštof Verner Jiří Žák Jaroslava Pertoldová Josef Šrámek Jiří Sedlák Jakub Trubač Patricie Týcová 《International Journal of Earth Sciences》2009,98(3):517-532
The Plechy pluton, southwestern Bohemian Massif, represents a late-Variscan, complexly zoned intrusive center emplaced near
the crustal-scale Pfahl shear zone; the pluton thus provides an opportunity to examine the interplay among successive emplacement
of large magma batches, magmatic fabric acquisition, and the late-Variscan stress field associated with strike-slip shearing.
The magmatic history of the pluton started with the emplacement of the porphyritic Plechy and Haidmühler granites. Based on
gravity and structural data, we interpret that the Plechy and Haidmühler granites were emplaced as a deeply rooted, ∼NE–SW
elongated body; its gross shape and internal fabric (steep ∼NE–SW magmatic foliation) may have been controlled by the late-Variscan
stress field. The steep magmatic foliation changes into flat-lying foliation (particularly recorded by AMS) presumably as
a result of divergent flow. Magnetic lineations correspond to a sub-horizontal ∼NE–SW finite stretch associated with the divergent
flow. Subsequently, the Třístoličník granite, characterized by steep margin-parallel magmatic foliation, was emplaced as a
crescent-shaped body in the central part of the pluton. The otherwise inward-younging intrusive sequence was completed by
the emplacement of the outermost and the most evolved garnet-bearing granite (the Marginal granite) along the southeastern
margin of the pluton.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
1000.
Habib Belayouni Angelida Di Staso Francesco Guerrera Manuel Martín Martín Crina Miclǎuş Francisco Serrano Mario Tramontana 《International Journal of Earth Sciences》2009,98(1):157-176
An integrated stratigraphic analysis has been made of the Tarcău Nappe (Moldavidian Domain, Eastern Romanian Carpathians),
coupled with a geochemical study of organic-rich beds. Two Main Sequence Boundaries (Early Oligocene and near to the Oligocene–Aquitanian
boundary, respectively) divide the sedimentary record into three depositional sequences. The sedimentation occurred in the
central area of a basin supplied by different and opposite sources. The high amount of siliciclastics at the beginning of
the Miocene marks the activation of the “foredeep stage”. The successions studied are younger than previously thought and
they more accurately date the deformation of the different Miocene phases affecting the Moldavidian Basin. The intervals with
black shales identified are related to two main separate anoxic episodes with an age not older than Late Rupelian and not
before Late Chattian. The most important organic-rich beds correspond to the Lower Menilites, Bituminous Marls and Lower Dysodilic
Shales Members (Interval 2). These constitute a good potential source rock for petroleum, with homogeneous Type II oil-prone organic matter, highly lipidic and thermally immature. The deposition of black shales has been interpreted as occurring
within a deep, periodically isolated and tectonically controlled basin. 相似文献