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261.
Karol Kozieł 《Earth, Moon, and Planets》1979,21(3):351-359
This paper presents historical stages of the development of methods concerning observation and theory of the Moon's rotation around its centre of mass from the beginning of the 17th century up to the present day. The accuracy and usefulness of these methods is estimated and a critical attitude is assumed towards the results concerning the values of constants of the Moon's physical libration. 相似文献
262.
M. Siarkowski J. Sylwester J. Bąkała Ż. Szaforz M. Kowaliński Z. Kordylewski S. Płocieniak P. Podgórski B. Sylwester W. Trzebiński M. Stȩślicki K. J. H. Phillips O. V. Dudnik E. Kurbatov V. D. Kuznetsov S. Kuzin I. V. Zimovets 《Experimental Astronomy》2016,41(3):327-350
Interhelioprobe (IHP), an analogue to the ESA Solar Orbiter, is the prospective Russian space solar observatory intended for in-situ and remote sensing investigations of the Sun and the inner heliosphere from a heliocentric orbit with the perihelion of about 60 solar radii. One of several instruments on board will be the Bragg crystal spectrometer ChemiX which will measure X-ray spectra from solar corona structures. Analysis of the spectra will allow the determination of the elemental composition of plasma in hot coronal sources like flares and active regions. ChemiX is under development at the Wroc?aw Solar Physics Division of the Polish Academy of Sciences Space Research Centre in collaboration with an international team (see the co-author list). This paper gives an overview of the ChemiX scientific goals and design preparatory to phase B of the instrument development. 相似文献
263.
The occurrence of specific micropollutants (MPs), indicators of domestic and hospital wastewater, was investigated in a river connected to a karst spring based on two sampling campaigns under varying flow conditions. The MPs characterized by a high frequency of occurrence (acesulfame-K, ibuprofen, gemfibrozil, nonylphenol, and iohexol) were highly reflective of wastewater discharged in ephemeral streams and tributaries, as well as specific point sources such as farms and hospital effluents. A mixing model based on chloride mass fluxes allows the quantification of the percentage of untreated wastewater effluents in inflowing water from river tributaries, which varied between 0.7–99% and 5.0–10% in low flow and high flow, respectively. The frequency of occurrence of MPs is related to the volume of wastewater input, extent of river dilution, persistence of the MPs, and type of point source contamination on the river. Relationships were established between MPs such as ibuprofen and acesulfame-K (ACE-K), indicating their co-existence in highly consumed generic medicine and their suitability as wastewater co-tracers. Additionally, the number of consumers of gemfibrozil (GEM) and acesulfame-K were estimated based on mass loads in the river tributaries for management purposes. Groundwater contamination is mostly due to diffuse and point sources infiltration occurring on the spring catchment, including the sinking stream that could contribute up to 17% to the mass loads of some micropollutants (e.g., ACE-K and GEM) at the spring. Nevertheless, the increase of MPs use with growing urbanization is expected to have a much significant impact on the groundwater quality in the future. 相似文献
264.
Jokubauskas Petras Bagiński Bogusław Macdonald Ray Krzemińska Ewa 《International Journal of Earth Sciences》2018,107(5):1623-1639
International Journal of Earth Sciences - The Kłodzko–Złoty Stok intrusion (KZSI), located in the NE part of the Bohemian Massif of Central Europe, has preserved records of the... 相似文献
265.
International Journal of Earth Sciences - This paper attempts to show the relationship between joints observed in flysch formations in the field and microfracture fabrics invisible to the naked eye... 相似文献
266.
267.
Joanna M. Nield Richard C. Chiverrell Stephen E. Darby Julian Leyland Larisa H. Vircavs Benjamin Jacobs 《地球表面变化过程与地形》2013,38(1):95-102
Tephra fallout from the 2011 Grímsvötn eruption onto Svínafellsjökull, Iceland, created an ice‐ash landscape of a type that is rarely studied but is nevertheless common in glacio‐volcanic regions. We used terrestrial laser scanning (TLS) to measure ice surface topography and absorption at high spatial resolution, confirming ablation rates either reduce or increase under thick (insulating) and thin (reduced albedo) ash deposits, respectively. Fourier transform analysis of the TLS data identified that a three‐fold increase in aerodynamic roughness was attributable to an increase in larger (> 0·2 m) surface features. Moreover, TLS measurements revealed the importance of ash redistribution by meltwater in generating differential melting which modifies roughness and ash patchiness, such that the net effect of these spatial ash–ice feedbacks was to reduce ablation rates by up to 59%. The modulating effects of these previously undocumented feedbacks on ablation rates are, therefore, significant and must be correctly parameterized if ash‐covered glacier mass balances are to be predicted correctly. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
268.
Alexander Barth Aida Alvera-Azcárate Jean-Marie Beckers Joanna Staneva Emil V. Stanev Johannes Schulz-Stellenfleth 《Ocean Dynamics》2011,61(5):599-610
Surface winds are crucial for accurately modeling the surface circulation in the coastal ocean. In the present work, high-frequency
radar surface currents are assimilated using an ensemble scheme which aims to obtain improved surface winds taking into account
European Centre for Medium-Range Weather Forecasts winds as a first guess and surface current measurements. The objective
of this study is to show that wind forcing can be improved using an approach similar to parameter estimation in ensemble data
assimilation. Like variational assimilation schemes, the method provides an improved wind field based on surface current measurements.
However, the technique does not require an adjoint, and it is thus easier to implement. In addition, it does not rely on a
linearization of the model dynamics. The method is validated directly by comparing the analyzed wind speed to independent
in situ measurements and indirectly by assessing the impact of the corrected winds on model sea surface temperature (SST)
relative to satellite SST. 相似文献
269.
Joanna K. York George B. McManus Wim J. Kimmerer Anne M. Slaughter Toni R. Ignoffo 《Estuaries and Coasts》2014,37(3):576-588
We investigated trophic relationships involving microzooplankton in the low salinity zone of the San Francisco Estuary (SFE) as part of a larger effort aimed at understanding the dynamics of the food web supporting the endangered delta smelt, Hypomesus transpacificus. We performed 14 cascade experiments in which we manipulated the biomass of a copepod (Limnoithona tetraspina, Pseudodiaptomus forbesi, or Acartiella sinensis) and quantified responses of lower trophic levels including bacterioplankton, phytoplankton, and microzooplankton. Microzooplankton comprised a major food source for copepods; 9 out of 14 experiments showed removal of at least one group of microzooplankton by copepods. In contrast, the impact of copepods on phytoplankton was indirect; increased copepod biomass led to greater growth of phytoplankton in 3 of 14 experiments. Estimated clearance rates on microzooplankton were 4 mL day?1 for L. tetraspina and 2–6 mL day?1 for P. forbesi, whereas A. sinensis consumed mainly copepod nauplii. Complex trophic interactions, including omnivory, among copepods, microzooplankton, and different components of the phytoplankton likely obscured clear trends. The food web of the SFE is probably less efficient than previously thought, providing poor support to higher trophic levels; this inefficient food web is almost certainly implicated in the continuing low abundance of fishes, including the delta smelt that use the low salinity zone of the San Francisco Estuary. 相似文献
270.
Planning the Colca Canyon and the Valley of the Volcanoes National Park in South Peru 总被引:1,自引:1,他引:0
The economic development of the Rio Colca region and related infrastructure endangers the environment of the deepest canyon worldwide. The unique values of the Colca Valley and Canyon and its tributary Valley of the Volcanoes are summarised. They include a magnificent, deep section of the orogenic belt 100 km long, different geological formations, active faults, a variety of fold structures, young volcanoes, hot springs, geysers, several ecological zones and the largest condor habitat in the Andes. Based on the observed land use, development and regional planning, the threats and conflict areas are outlined. Studies performed by the Polish Scientific Expedition to Peru since 2003 add greatly to the knowledge of geology, landscape and pioneering biota development of the area and its importance to the world heritage of nature. They are aimed to give scientific background to the project of the Canyon Colca and Valley of the Volcanoes National Park. The article gives the proposed limits of the park and its buffer zones, categories of protection zones compatible with the SINANPE system of Peru and suggestions on tourist accessibility. The strict protection zone should cover the most inaccessible part of the area where human economic activity practically does not exist. Traditional farming and animal husbandry, wildlife, cultural tourism and some forms of adventure tourism will be allowed in the zone of special usage. The new park would strengthen the relatively poor system of the protected areas in the Arequipa Department, increase tourist attractiveness and determine constraints for sustained regional development. The expected actions of the park authority and local governments are specified. 相似文献