全文获取类型
收费全文 | 59985篇 |
免费 | 744篇 |
国内免费 | 431篇 |
专业分类
测绘学 | 1261篇 |
大气科学 | 3920篇 |
地球物理 | 11665篇 |
地质学 | 21529篇 |
海洋学 | 5653篇 |
天文学 | 13798篇 |
综合类 | 109篇 |
自然地理 | 3225篇 |
出版年
2022年 | 385篇 |
2021年 | 721篇 |
2020年 | 708篇 |
2019年 | 814篇 |
2018年 | 1688篇 |
2017年 | 1525篇 |
2016年 | 1796篇 |
2015年 | 907篇 |
2014年 | 1637篇 |
2013年 | 3108篇 |
2012年 | 1873篇 |
2011年 | 2506篇 |
2010年 | 2303篇 |
2009年 | 2963篇 |
2008年 | 2493篇 |
2007年 | 2705篇 |
2006年 | 2440篇 |
2005年 | 1746篇 |
2004年 | 1698篇 |
2003年 | 1657篇 |
2002年 | 1631篇 |
2001年 | 1461篇 |
2000年 | 1300篇 |
1999年 | 1075篇 |
1998年 | 1073篇 |
1997年 | 1092篇 |
1996年 | 879篇 |
1995年 | 861篇 |
1994年 | 807篇 |
1993年 | 713篇 |
1992年 | 699篇 |
1991年 | 653篇 |
1990年 | 663篇 |
1989年 | 664篇 |
1988年 | 607篇 |
1987年 | 709篇 |
1986年 | 637篇 |
1985年 | 785篇 |
1984年 | 819篇 |
1983年 | 759篇 |
1982年 | 682篇 |
1981年 | 718篇 |
1980年 | 610篇 |
1979年 | 605篇 |
1978年 | 576篇 |
1977年 | 554篇 |
1976年 | 497篇 |
1975年 | 496篇 |
1974年 | 488篇 |
1973年 | 530篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Stotts S. A Koch R. A. Joshi S. M. Nguyen V. T. Ferreri V. W. Knobles D. P. 《Oceanic Engineering, IEEE Journal of》2010,35(1):79-102
982.
A series of samples of inhabitants of hydrothermal vents were collected during the 12th cruise of R/V Akademik Mstislav Keldysh in Guaymas Basin (the Gulf of California) and the Axial Seamount area (Juan de Fuca Ridge). The concentrations of trace and heavy metals in the tissues of Ridgeia piscesae, Riftia pachyptila, and Paralvinella palmiformis were analyzed. The neutron-activation analysis revealed significantly higher concentrations of uranium in the tissues of Paralvinella palmiformis as compared to the ambient seawater. The possible reasons for such phenomenon are discussed. The data obtained by the neutron-activation method are compared with those obtained by the atomic-absorption method for the same tissues analyzed. 相似文献
983.
984.
H. Htún M.R. Payne G. Beaugrand P.C. Reid A.B. Sand H. Drange B. Hansen J.A. Jacobsen D. Bloch 《Progress in Oceanography》2009,80(3-4):149-162
Pronounced changes in fauna, extending from the English Channel in the south to the Barents Sea in the north-east and off Greenland in the north-west, have occurred in the late 1920s, the late 1960s and again in the late 1990s. We attribute these events to exchanges of subarctic and subtropical water masses in the north-eastern North Atlantic Ocean, associated with changes in the strength and extent of the subpolar gyre. These exchanges lead to variations in the influence exerted by the subarctic or Lusitanian biomes on the intermediate faunistic zone in the north-eastern Atlantic. This strong and persistent bottom-up bio-physical link is demonstrated using a numerical ocean general circulation model and data on four trophically connected levels in the food chain – phytoplankton, zooplankton, blue whiting, and pilot whales. The plankton data give a unique basin-scale depiction of these changes, and a long pilot whale record from the Faroe Islands offers an exceptional temporal perspective over three centuries. Recent advances in simulating the dynamics of the subpolar gyre suggests a potential for predicting the distribution of the main faunistic zones in the north-eastern Atlantic a few years into the future, which might facilitate a more rational management of the commercially important fisheries in this region. 相似文献
985.
986.
We present a model of the processes of development in the ecosystem of the coastal zone of the sea constructed by the method
of adaptive balance of causes (ABC-method). The model contains nine variables (phyto- and zooplankton, fish larvae, fishes, oxygen, carbon dioxide, salinity,
biogenic elements, and detritus) affected by the solar radiation, surface wind, sea temperature, and river discharge. The
equations of the model contain control agents governing the dependences of the elements of the food chain on the vitally important
resources and environmental conditions. The scenarios of the processes of development are constructed for the simulated annual
courses of external actions. The possibility of management of fish resources by regulating the flows of biogenic elements
and detritus with river discharge is discussed. A mechanism of management based on the monitoring of the concentration of
dissolved oxygen in seawater is proposed. The numerical experiments show that the ABC-model of the processes of development in the ecosystem of the coastal zone of the sea makes it possible to simulate the scenarios
of regulation of the flows of biogenic elements and detritus into the sea with an aim of preservation of of fish resources.
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 36–49, January–February, 2009. 相似文献
987.
D. V. Kulyamin E. M. Volodin V. P. Dymnikov 《Izvestiya Atmospheric and Oceanic Physics》2009,45(1):37-54
The problem of simulating quasi-biennial oscillations (QBOs) of zonal velocity in the equatorial stratosphere in atmospheric general circulation models is considered. In accordance with the results from Part I of this study on the basis of the models developed at the Institute of Numerical Mathematics of the Russian Academy of Sciences (INM RAS), the possibility of implementing (in these models) mechanisms of QBO excitation through both the interaction of planetary waves with the mean flow and breaking of short gravity waves is investigated. A new high-resolution 2° × 2.5° × 80 version of the INM RAS model is designed, a climate simulation with the two 2° × 2.5° × 39 and 2° × 2.5° × 80 versions of the INM RAS model is briefly described, results of spectral analysis of equatorial wave activity are presented, and the QBO formation processes in these models are considered in detail. For the new 2° × 2.5° × 80 model, realistic QBOs of zonal wind are obtained as the result of the action of both mechanisms. 相似文献
988.
A. V. Vivchar K. B. Moiseenko R. A. Shumskii A. I. Skorokhod 《Izvestiya Atmospheric and Oceanic Physics》2009,45(3):302-313
The task of identifying climatically significant regional anthropogenic emissions and estimating their contribution to the variability of nitrogen oxides observed at a monitoring station is considered on the basis of NO and NO2 surface concentrations measured at the Zotino background observation station (60°26′ N, 89°24′ E, Krasnoyarsk Territory). The approach used is based on an estimation of the conditional probability of polluted air arriving from individual regions by using the results of calculating backward Lagrangian trajectories in the lower troposphere. It is established that the contribution of air masses supplied from industrial regions in the south of the Krasnoyarsk Territory to episodes of high concentrations of nitrogen oxides (>0.7 ppb) is larger than the contribution from cities and towns located in the south of Western Siberia. The results indicate that anthropogenic sources of pollution substantially affect the balance of minor gases in the lower troposphere on a regional scale and that this factor must be taken into account when observational data from the Zotino background station are analyzed and interpreted. 相似文献
989.
DING Keqin DUAN Menglan FU Pinsheng LIU Chuntu
Ph. D. Associate Professor Research Department Center of Boiler Pressure Vessel Inspection Research Beijing P. R. China
Ph. D. Research Professor CCS Research Development Center China Classification Society Beijing P. R. China
Lecturer Yumen Petroleum School of Technique Technology Yumen P. R. China Research Professor 《中国海洋工程》1999,(4)
A simple probabilistic model for predicting crack growth behavior under random loading is pre-sented.In the model,the parameters c and m in the Paris-Erdogan Equation are taken as random variables,and their stochastic characteristic values are obtained through fatigue crack propagation tests on an offshorestructural steel under constant amplitude loading.Furthermore,by using the Monte Carlo simulation tech-nique,the fatigue crack propagation life to reach a given crack length is predicted.The tests are conducted toverify the applicability of the theoretical prediction of the fatigue crack propagation. 相似文献
990.
High-resolution seismic profiles across the shelf margin and trough region of the Korea Strait reveal five shallow, near-surface facies units. These are relict coastal deposits, relict delta deposits, slumps and slides, and trough lag deposits. Most deposits represent a lowstand systems tract, formed during the last lowstand of sea level. Relict coastal deposits represent a linear sediment body along the present shelf margin at water depths of 120–150 m, whereas relict delta deposits occur on the gentle, southwestern slope of the trough at water depths of about 150–200 m. Slumps and slides are dominant at the base of slope in the central trough region. Sediments on the central trough floor were partly eroded and redistributed by strong currents, resulting in lag deposits. 相似文献