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301.
Urban impacts analysis on hydrochemical and hydrogeological evolution of groundwater in shallow aquifer Linares,Mexico 总被引:1,自引:1,他引:0
René?Alberto?Dávila PórcelEmail author Héctor?De?León Gómez Christoph?Schüth 《Environmental Earth Sciences》2012,66(7):1871-1880
In northeast Mexico is Linares City, which has an extensive agricultural area and many industrial activities. Near this city
is the Cerro-Prieto Dam (~12 km NE direction); this drinking water reservoir captures the water of the Pablillo River catchment
area and constitutes an important source of potable water for the metropolitan area of Monterrey, the largest urban center
of this region. Groundwater sources in this area provide drinking water to Linares inhabitants. A hydrogeological and hydrochemical
study was conducted on the shallow aquifers surrounding the urban centers (Linares and Hualahuises) to determine the evolution
of the water quality between 1981 and 2009. The hydrochemistry was assessed upgradient and downgradient from the potential
contamination sources in Linares city. Groundwater showed a chemical evolution from calcium-bicarbonate type to calcium–sodium-sulfate
type. The water qualities in the downstream area after Linares are inferior compared to the upstream area before the city.
Nitrate concentrations in groundwater increased significantly after 28 years indicating an important pollutant process in
this period of time over the study area. The possible pollution sources could be the agricultural and farm activities, industrial
development, landfills leachate, septic tanks and wastewater of municipal and domestic consumption. If the present scenario
continues, an aquifer vulnerability assessment would be important for the sustainable water management. 相似文献
302.
H. Pfletschinger I. Engelhardt M. Piepenbrink F. Königer R. Schuhmann A. Kallioras C. Schüth 《Environmental Earth Sciences》2012,65(5):1523-1533
For the determination of groundwater recharge processes in arid environments, vadose zone water fluxes and water storage should
be considered. To better understand and quantify vadose zone processes influencing groundwater recharge, a soil column experimental
setup has been developed that mimics arid atmospheric conditions and measures water and temperature fluxes in high temporal
and spatial resolution. The focus of the experiment was on the determination of water infiltration, redistribution, evaporation
and percolation under non-isothermal conditions. TDR rod sensors and a specific TDR “Taupe” cable sensor were used for water
content measurements and allowed the infiltration fronts to be traced over the whole column length. Applying single irrigations
of different amount and intensity showed the applicability of the experimental setup for the measurement of water movement
in the unsaturated soil column. 相似文献
303.
A. Gandorfer B. Grauf P. Barthol T. L. Riethm��ller S. K. Solanki B. Chares W. Deutsch S. Ebert A. Feller D. Germerott K. Heerlein J. Heinrichs D. Hirche J. Hirzberger M. Kolleck R. Meller R. M��ller R. Sch?fer G. Tomasch M. Kn?lker V. Mart��nez?Pillet J. A. Bonet W. Schmidt T. Berkefeld B. Feger F. Heidecke D. Soltau A. Tischenberg A. Fischer A. Title H. Anwand E. Schmidt 《Solar physics》2011,268(1):35-55
We describe the design of the Sunrise Filter Imager (SuFI) and the Image Stabilization and Light Distribution (ISLiD) unit onboard the Sunrise balloon borne solar observatory. This contribution provides the necessary information which is relevant to understand the instruments?? working principles, the relevant technical data, and the necessary information about calibration issues directly related to the science data. 相似文献
304.
Nils Reiche Tanja Westerkamp Steffen Lau Helko Borsdorf Peter Dietrich Claudia Schütze 《Environmental Earth Sciences》2014,72(5):1435-1441
Today, ground-based optical remote sensing (ORS) has become an intensively used method for quantifying pollutant or greenhouse gas emissions from point or area sources, and for the validation of airborne or satellite remote sensing data. In this study, we present the results of a release experiment using acetylene (C2H2) as a tracer gas, where three ORS techniques were simultaneously tested for two main purposes: (1) the detection of emission sources and (2) the quantification of release rates. Therefore, passive and active open-path Fourier transform infrared spectroscopy (OP-FTIR) and open-path tunable diode laser absorption spectroscopy (TDLAS) were applied and evaluated. The concentration results of the active ORS methods are compared to those estimated by a Lagrangian stochastic atmospheric dispersion model. Our results reveal that passive OP-FTIR is a valuable tool for the rapid detection and imaging of emission sources and the spatial tracer gas distribution; while with active OP-FTIR and TDLAS, C2H2 concentrations in the sub-ppm range could be quantified that correlated well with the concentration data obtained by our modeling approach. 相似文献
305.
306.
Larryn W. Diamond Alexandre Tarantola Holger Stünitz 《Contributions to Mineralogy and Petrology》2010,160(6):845-864
Fluid inclusions in quartz are known to modify their densities during shear deformation. Modifications of chemical composition
are also suspected. However, such changes have not been experimentally demonstrated, their mechanisms remain unexplained,
and no criteria are available to assess whether deformed inclusions preserve information on paleofluid properties. To address
these issues, quartz crystals containing natural CO2–H2O–NaCl fluid inclusions have been experimentally subjected to compressive deviatoric stresses of 90–250 MPa at 700°C and ~600 MPa
confining pressure. The resulting microcracking of the inclusions leads to expansion by up to 20%, producing low fluid densities
that bear no relation to physical conditions outside the sample. Nevertheless, the chemical composition of the precursor inclusions
is preserved. With time the microcracks heal and form swarms of tiny satellite inclusions with a wide range of densities,
the highest reflecting the value of the maximum principle stress, σ
1. These new inclusions lose H2O via diffusion, thereby passively increasing their salt and gas contents, and triggering plastic deformation of the surrounding
quartz via H2O-weakening. Using microstructural criteria to identify the characteristic types of modified inclusions, both the pre-deformation
fluid composition and syn-deformation maximum stress on the host mineral can be derived from microthermometric analysis and
thermodynamic modelling. 相似文献
307.
Torben Schüler 《GPS Solutions》2006,10(2):108-125
Many kinematic GPS applications rely on high accuracy, which usually requires the ambiguities to be fixed. Normally, a reference station in the rover’s vicinity is needed for successful ambiguity resolution. Alternatively, a network surrounding the rover and allowing one to derive area correction parameters is needed. Unfortunately, both approaches are not feasible in certain situations. This paper is a contribution to precise kinematic positioning over long baselines. Atmospheric refraction becomes critical in the error budget, but progress has been made to use numerical weather models to derive tropospheric corrections, for instance. The spatial correlation of both ionospheric and tropospheric propagation delays is investigated in this paper and special attention is paid on the systematic error behavior of tropospheric refraction. The principles developed are applied to an extended reliability test of the ambiguities. Finally, it is demonstrated in positioning experiments that kinematic positioning retrieval with fixed ambiguities is actually possible for baselines between 150 and 300 km with an accuracy of approximately 2 cm in post-mission processing.
相似文献
Torben SchülerEmail: Phone: +49-89-60042587Fax: +49-89-60043019 |
308.
Helama S Schöne BR Kirchhefer AJ Nielsen JK Rodland DL Janssen R 《Marine environmental research》2007,63(3):185-199
Annual growth increments were examined from shells of the ocean quahog (Arctica islandica L.) from northwest Norway and from tree-ring samples of the Scots pine (Pinus sylvestris L.) from nearby coastal areas. The reconstructed annual growth increments were used to compare growth variability in marine and terrestrial ecosystems. Spatiotemporal comparison of the growth records showed statistically significant correlation during the 19th century A.D., indicative of ecosystem-independent response to pre-anthropogenic climate variations. Geographical correlation between marine and terrestrial records was only observed at the local scale. Years with particularly low winter or high summer North Atlantic Oscillation (NAO) indices showed the best synchronization of marine and terrestrial growth. Despite strong correlation during historical time, our palaeoecological evidence suggests that marine and terrestrial ecosystems may show dissimilar growth reaction to recently observed positive winter-NAO phases. 相似文献
309.
Dr. H. M. E. Schürmann 《International Journal of Earth Sciences》1924,14(3):239-252
Ohne Zusammenfassung 相似文献
310.
The global energy balance from a surface perspective 总被引:1,自引:1,他引:0
Martin Wild Doris Folini Christoph Schär Norman Loeb Ellsworth G. Dutton Gert König-Langlo 《Climate Dynamics》2013,40(11-12):3107-3134
In the framework of the global energy balance, the radiative energy exchanges between Sun, Earth and space are now accurately quantified from new satellite missions. Much less is known about the magnitude of the energy flows within the climate system and at the Earth surface, which cannot be directly measured by satellites. In addition to satellite observations, here we make extensive use of the growing number of surface observations to constrain the global energy balance not only from space, but also from the surface. We combine these observations with the latest modeling efforts performed for the 5th IPCC assessment report to infer best estimates for the global mean surface radiative components. Our analyses favor global mean downward surface solar and thermal radiation values near 185 and 342 Wm?2, respectively, which are most compatible with surface observations. Combined with an estimated surface absorbed solar radiation and thermal emission of 161 and 397 Wm?2, respectively, this leaves 106 Wm?2 of surface net radiation available globally for distribution amongst the non-radiative surface energy balance components. The climate models overestimate the downward solar and underestimate the downward thermal radiation, thereby simulating nevertheless an adequate global mean surface net radiation by error compensation. This also suggests that, globally, the simulated surface sensible and latent heat fluxes, around 20 and 85 Wm?2 on average, state realistic values. The findings of this study are compiled into a new global energy balance diagram, which may be able to reconcile currently disputed inconsistencies between energy and water cycle estimates. 相似文献