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961.
Similarity solutions, describing the flow of a perfect gas behind spherical shock waves, are investigated including the radiation heat flux. The shock is assumed to be propagating in a medium at rest. Shock radius varies exponentially with time and density is inversely proportional to fifth power of the shock radius immediately ahead of the shock front. 相似文献
962.
A numerical study of the nocturnal heat island over a medium-sized mid-latitude city (Columbus,Ohio) 总被引:4,自引:0,他引:4
James L. McElroy 《Boundary-Layer Meteorology》1973,3(4):442-453
A numerical investigation is conducted of the nocturnal heat island over Columbus, Ohio, a relatively flat mid-latitude city. Specifically, a cross-sectional steady-state numerical model to simulate the (thermal) structure of the nocturnal urban boundary layer is developed from a one-dimensional, time-dependent model due to Estoque. The model is applied to Columbus for special periods in September 1968 and March 1969 during which comparable experimental data were collected. The numerical simulations agree well with the observed data with respect to the detailed spatial form of the surface-based thermal boundary layer across the city. The use of the model for other metropolitan areas, for ascertaining the relative effect of city size and building geometry on the development of the thermal boundary layer, and for determining the effect of alternate land-use strategies on the thermal stratification are also discussed.Digest of portion of a dissertation submitted to the Pennsylvania State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy.Presented in part at the Air Pollution, Turbulence and Diffusion Symposium, Las Cruces, New Mexico, 7–10 December 1971.On assignment from the National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce. 相似文献
963.
Siliceous microfossil assemblage succession was analyzed in a 100 m sediment core from Lake Baikal, Siberia. The core was recovered from the lake's central basin at a water depth of 365 m. Microfossil abundance varied greatly within the intervals sampled, ranging from samples devoid of siliceous microfossils to samples with up to 3.49 × 1011 microfossils g-1 sediment. Fluctuations in abundance appear to reflect trends in the marine 18O record, with peak microfossil levels generally representing climate optima. Microfossil taxa present in sampled intervals changed considerably with core depth. Within each sample a small number of endemic diatom species dominated the assemblage. Changes in dominant endemic taxa between sampled intervals ranged from extirpation of some taxa, to shifts in quantitative abundance. Differences in microfossil composition and the association of variations in abundance with climate fluctuations suggest rapid speciation in response to major climatic excursions. 相似文献
964.
Nikolay A. Sokolov 《Astrophysics and Space Science》2010,325(1):37-40
We presented a phenomenological mode that attributes the precession of perihelion of planets to the relativistic correction.
This modifies Newton’s equation by adding an inversely cube term with distance. The total energy of the new system is found
to be the same as the Newtonian one. Moreover, we have deduced the deflection of light formula from Rutherford scattering.
The relativistic term can be accounted for quantum correction of the gravitational potential and/or self energy of objects. 相似文献
965.
The control of synchronous structures on formation of superlarge stratabound ore deposits is immense. Based on studies of ore deposits in South Qiniing, northern Guangdong, Langshan and other areas, three new ideas in comparison with examples of ore control of synchronous structures both in China and abroad are proposed: (i) multiorder ore control of synchronous structures, which means that synchronous structures of different orders display different controls on ore deposits; (ii) synchronous structures in different stages of basin evolution display different controls on basin fluid system and ore-forming system; (iii) synchronous strurture accompanying hydrothermal mineralization as a preexisting weak surface in earth crust often reactivate in later tcctono-thermal event to be a channelway for magma or thermal fluids which superimposed on and reformed preexisting ore beds to form large or superlarge composite ore deposits. 相似文献
966.
A new method is presented to search for hydraulically transmissive features in open boreholes in bedrock. A flexible borehole liner made of a watertight, nylon fabric is filled with water to create a constant driving head to evert (reverse of invert) the liner down the hole so that the liner pushes the borehole water out into transmissive fractures or other permeable features. The descent rate is governed by the bulk transmissivity of the remaining permeable features below the liner. Initially, the liner descent rate or velocity is a measure of transmissivity (T) of the entire hole. As the everting liner passes and seals each permeable feature, changes in the liner velocity indicate the position of each feature and an estimate of T using the Thiem equation for steady radial flow. This method has been performed in boreholes with diameters ranging from 96 to 330 mm. Profiling commonly takes a few hours in holes 200‐ to 300‐m long. After arrival of the liner at the bottom of the hole, the liner acts as a seal preventing borehole cross connection between transmissive features at different depths. Liner removal allows the hole to be used for other purposes. The T values determined using this method in a dolostone aquifer were found to be similar to the values from injection tests using conventional straddle packers. This method is not a replacement for straddle‐packer hydraulic testing of specific zones where greater accuracy is desired; however, it is effective and efficient for scanning entire holes for transmissive features. 相似文献
967.
Introduction The Western Kunlun Mountain Pass M=8.1 earthquake occurred on November 14, 2001 is the other M=8 earthquake occurred 50 years after Dangxiong, Tibet M=8.0 earthquake in Chinese mainland. The earthquake has caused the attention of the seismologists in the following aspects: 1) The fracture length is more than 400 km, which is far away from the estimated length by the statistic empirical function between the magnitude and the fracture length (WANG, et al, 2002); 2) The aftersh… 相似文献
968.
MENGLi-li 《中国地理科学(英文版)》2003,13(2):190-192
The exploitation and utilization of the tour resources of tournament athletics, including skiling, boat sail-ing, archery, ice engraving, snow engraving, has become a new trend of the development of Chinese tourism. Due tothe unique cold climate and superior geographic location, Harbin is a promising city for developing tour resources of tourna-ment athletics. Based on the analysis of the superiority and peculiarity of Harbin, the speculation on development of tour resources of tournament athletics in Harbin is proposed as follows : 1 ) Harbin should develop its special tour resources of tournament athletics associated with needs of market; 2) Harbin should take the advantages of rich resources and devel-op ice and snow entertainment in winter and travel for sight-seeing and spending summer;, 3) the adjustment of the layoutof ice and snow resources should be based on the idea of taking Harbin as the center and all-side opening at the largescale in the way of radiation; 4) tourism should be developed by the combined efforts of various departments to make feasi-ble plan, and the organizers should pay much attention to ensuring the safetv of tourists. 相似文献
969.
970.
In September 1984, the freshwater input to the Eastmain River (James Bay, Canada) was increased by a factor of 50 over a 6-d period during a controlled reservoir discharge. Changes to the current, salinity and turbidity regimes were monitored during the peak runoff. Estuarine salinity values fell rapidly with increasing mean flow, as did the amplitude of the semi-diurnal tidal currents. A large increase in bottom shear stress dispersed the settled suspension layer into the water column, raising concentrations of suspended matter in the estuary by a factor of 4 in 3 d. The peak values exceeded 150 mg I?1. This led to erosion of the river silt deposits, with the export of an estimated 6 × 104 metric tons of sediments. After the reduction of discharge, current values returned to their normal range within a day, whereas upstream salinity intrusion occurred at a slower rate. Horizontal diffusivities of about 100 m2 s?1 were required to match the observed lag. 相似文献