全文获取类型
收费全文 | 38361篇 |
免费 | 285篇 |
国内免费 | 220篇 |
专业分类
测绘学 | 771篇 |
大气科学 | 1776篇 |
地球物理 | 7577篇 |
地质学 | 14940篇 |
海洋学 | 3560篇 |
天文学 | 9016篇 |
综合类 | 102篇 |
自然地理 | 1124篇 |
出版年
2022年 | 499篇 |
2021年 | 718篇 |
2020年 | 764篇 |
2019年 | 833篇 |
2018年 | 1728篇 |
2017年 | 1576篇 |
2016年 | 1693篇 |
2015年 | 648篇 |
2014年 | 1468篇 |
2013年 | 2095篇 |
2012年 | 1643篇 |
2011年 | 1931篇 |
2010年 | 1834篇 |
2009年 | 2027篇 |
2008年 | 1799篇 |
2007年 | 2007篇 |
2006年 | 1763篇 |
2005年 | 919篇 |
2004年 | 840篇 |
2003年 | 824篇 |
2002年 | 768篇 |
2001年 | 784篇 |
2000年 | 652篇 |
1999年 | 429篇 |
1998年 | 454篇 |
1997年 | 489篇 |
1996年 | 366篇 |
1995年 | 374篇 |
1994年 | 356篇 |
1993年 | 309篇 |
1992年 | 306篇 |
1991年 | 304篇 |
1990年 | 350篇 |
1989年 | 294篇 |
1988年 | 273篇 |
1987年 | 277篇 |
1986年 | 212篇 |
1985年 | 312篇 |
1984年 | 317篇 |
1983年 | 316篇 |
1982年 | 295篇 |
1981年 | 264篇 |
1980年 | 280篇 |
1979年 | 220篇 |
1978年 | 261篇 |
1977年 | 226篇 |
1976年 | 193篇 |
1975年 | 199篇 |
1974年 | 182篇 |
1973年 | 218篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
L. P. Golobokova V. E. Pavlov I. V. Khvostov T. V. Khodjer 《Izvestiya Atmospheric and Oceanic Physics》2011,47(3):329-335
We consider the resemblance between the ion composition of the fraction of soluble aerosols and gaseous admixtures in the atmospheric surface layer at the high-level Mondy station (East Sayan), those in the Listvyanka settlement south of Lake Baikal, in the city of Irkutsk, and at the Primorskaya station near the city of Ussuriysk (Primorskii krai). We use measurement data on the concentrations of the following ions: HCO 3 ? , SO 4 2? , NO 3 ? , Cl?, H+, Na+, K+, Mg2+, Ca2+ in the soluble fraction of aerosols and gases HNO3, HCl, NH3, and SO2 in air samples over a 10-year period conducted in the mode of online monitoring. We found the lognormal form of distributions of concentrations of each of the abovementioned components according to the number of samples. A versatile scheme of the distribution of mean geometric concentrations of atmospheric components was proposed for all four groups. 相似文献
992.
993.
E. F. Mikhailov V. V. Merkulov S. S. Vlasenko T. I. Ryshkevich U. J. Pöschl 《Izvestiya Atmospheric and Oceanic Physics》2011,47(6):747-759
We describe a new differential analyzer implementing a technique for studying the hygroscopic properties of filter-precipitated aerosol particles based on a katharometric measurement of the amount of water vapor absorbed by an aerosol sample. The instrument has been tested on particles of sodium chloride and ammonium sulphate. A comparison of our data with the results of analogous measurements described in literature shows that the suggested technique has several important advantages, i.e., (1) higher sensitivity, which allows the measurement of particles of no more than 0.1 mg in mass; (2) a wide range of relative humidity variations (up to 99% at an accuracy of 0.06% RH at the upper-range value); (3) the absence of intermediate measurement steps connected with the need to account for water absorption by elements of a measurement system; and (4) the absence of restrictions to the size and shape of particles studied. In addition, the measurement technique rules out the possibility of errors caused by the kinetic effects of mass transport in the aerosol-water vapor system. 相似文献
994.
995.
Ye. I. Polyakova Ye. A. Novichkova A. P. Lisitzin V. P. Shevchenko M. D. Kravchishina 《Oceanology》2016,56(2):289-300
Diatom algae, aquatic palynomorphs, and the grain-size of surface sediments from bays of the White Sea were investigated in a program dedicated to the study of marginal filters (MF) in the Severnaya Dvina, Onega, and Kem rivers. Three microalgal assemblages are established in surface sediments, which replace each other successively with distance from river mouths and are characterized by a gradual decrease in a share of freshwater species of diatoms and Chlorophyceae algae, significantly varying concentrations of marine diatoms and dinocysts due to changes in water salinity, grain-size composition of sediments, quantitative distribution of suspended particulate matter (SPM), and water productivity at different marginal filter stages. 相似文献
996.
The surface M
2 tide in the Canadian Arctic Archipelago (CAA) is reproduced on the basis of the QUODDY-4 three-dimensional finite-element
hydrodynamic model. Particular emphasis has been placed on comparing model estimates for the amplitudes and phases of tidal
elevations and the parameters of ellipses (major semiaxis and eccentricity) of the barotropic tidal current velocity with
observational data. We present their spatial distributions and the distributions of averaged (over a tidal cycle) values of
the density, horizontal transfer, and dissipation rate of barotropic tidal energy. It is found that the CAA is a much less
effective dissipator of barotropic tidal energy than the World Ocean. 相似文献
997.
Oceanology - The variability of sea ice in the Weddell Sea, along with melting of glaciers of the Antarctic Peninsula and ice shelves, determines the volumes of melt water entering the water area,... 相似文献
998.
Analytical solutions for generalizing the Ekman stationary flow of a viscous incompressible fluid in an infinite layer are obtained. The solution of an overdetermined system of the Oberbeck–Boussinesq equations is considered. It is suggested to use a class of exact solutions for this problem. It is shown that the structure of the solutions allows one to preserve the advective derivative in the heat-conductivity equation; this makes it possible to model the stratification of the temperature and pressure fields and describe the oceanic countercurrents. 相似文献
999.
The interannual variation of the monthly average (weighted average) concentrations of particulate organic phosphorus (PPOM) in the photosynthetic layer, oxycline, redox zone, and H2S zone in the open Black Sea is estimated based on long-term observation data. The suspension sedimentation rates from the studied layers are assessed using model calculations and published data. The annual variation of PPOM sediment fluxes from the photosynthetic layer, oxycline, redox zone, and upper H2S zone to the anaerobic zone of the sea and the correspondingly annual average values are estimated for the first time. A regular decrease in the PPOM annual average flux with depth in the upper active layer is demonstrated. A correlation between the annual average values of PPOM sediment flux from the photosynthetic layer and ascending phosphate flux to this layer is shown, which suggests their balance in the open sea. The results are discussed in terms of the phosphorus biogeochemical cycle and the concept of new and regenerative primary production in the open Black Sea. 相似文献
1000.
Malakhova T. V. Kanapatskiy T. A. Sidorov I. G. Rusanov I. I. Malakhova L. V. Proskurnin V. Yu. Pimenov N. V. 《Oceanology》2018,58(6):909-917
Oceanology - A seasonal study of microbial methane oxidation (MO) and sulfate reduction (SR) processes in bottom sediments was carried out at five stations in the estuarian Sevastopol coastal area,... 相似文献