首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   85475篇
  免费   1137篇
  国内免费   526篇
测绘学   1755篇
大气科学   5606篇
地球物理   16253篇
地质学   30798篇
海洋学   7868篇
天文学   19907篇
综合类   222篇
自然地理   4729篇
  2022年   619篇
  2021年   1048篇
  2020年   1115篇
  2019年   1247篇
  2018年   2550篇
  2017年   2360篇
  2016年   2718篇
  2015年   1354篇
  2014年   2616篇
  2013年   4486篇
  2012年   2862篇
  2011年   3693篇
  2010年   3373篇
  2009年   4265篇
  2008年   3716篇
  2007年   3830篇
  2006年   3550篇
  2005年   2523篇
  2004年   2447篇
  2003年   2282篇
  2002年   2272篇
  2001年   1971篇
  2000年   1955篇
  1999年   1536篇
  1998年   1595篇
  1997年   1466篇
  1996年   1243篇
  1995年   1242篇
  1994年   1042篇
  1993年   1007篇
  1992年   934篇
  1991年   967篇
  1990年   936篇
  1989年   817篇
  1988年   751篇
  1987年   883篇
  1986年   773篇
  1985年   946篇
  1984年   1070篇
  1983年   1031篇
  1982年   950篇
  1981年   891篇
  1980年   792篇
  1979年   749篇
  1978年   726篇
  1977年   618篇
  1976年   626篇
  1975年   613篇
  1974年   589篇
  1973年   656篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This paper presents the results of three-dimensional acoustic seabed mapping in the region of the Taman Peninsula in the Black Sea using an interferometric side-scan sonar and an acoustic profiler. Mapping has revealed underwater objects identified as manifestations of underwater mud volcanism. Detailed analysis of sonar images of the relief and seabed profiles in the region of the objects has confirmed the original hypothesis.  相似文献   
992.
993.
Izvestiya, Atmospheric and Oceanic Physics - International investigations into the correlation between tropical cyclones (TCs) and the ionosphere are associated with great difficulties in proving...  相似文献   
994.
The first data on the chemical composition of dispersed matter from sedimentary traps are reported. The suspended components of sedimentary matter (amorphous silica, organic matter, carbonates, and lithogenic material, as well as Fe, Mn, and minor elements) are considered. As a result, it is shown that the intraannual variability in vertical fluxes of sedimentary matter is characterized by a seasonal increase in spring and autumn. The high fluxes of the components of sedimentary matter on the northern and southern slopes of the Derbent Basin in winter are explained by precipitation of material from the nepheloid layer that forms over the contour current.  相似文献   
995.
The results of comprehensive research into the area of the upper reach of the Mzymta River (Western Caucasus) are presented. The evidence of strong earthquakes that struck the study area throughout history is studied. The periods when mud flows and rockslides associated with the earthquakes are identified to fall between 3100–4000 and 700–1200 years ago. Paleoseismological results are correlated to the results of archeological excavations. As a result, it is revealed that the periods of tectonic disasters coincided with the onsets of the period when the area was uninhabited (abandoned) by people. The results of the present comprehensive research provide additional information to specify the seismic hazard and the chronology of human habitation in the region.  相似文献   
996.
This paper is devoted to the detection and identification of icebergs in the Russian Arctic Seas from the use of high- and medium-resolution radar and optical images from EROS-B, Radarsat-1, Radarsat-2, SPOT-4 and SPOT-5 Earth observation satellites. In July–September of 2011–2013, the SCANEX Research and Development Center, the Federal State Unitary Enterprise Atomflot, and other partner organizations provided operational satellite monitoring of icebergs in the Kara Sea and the Laptev Sea. More than 130 highly detailed optical and radar images were received and processed. The Vilkitsky Strait—one of the narrowest and most dangerous places within the Northern Sea Route—was chosen as an experimental polygon. As a result, iceberg location in the strait during the 2011–2013 navigation periods was analyzed, as were the iceberg size, area, drift direction, and height.  相似文献   
997.
998.
Issues of the formation and recording of the spatial and angular distributions of thermal radio radiation of rainfall in the microwave range are discussed. The thermal radio-frequency radiative transfer in a threedimensional rain cell is simulated numerically with a different rainfall rate, taking into account the nonspherical shape of falling raindrops and their size distribution. The role of the three-dimensional inhomogeneity of rainfall fields in the formation of a field of their inherent thermal radio radiation in the microwave range is revealed.  相似文献   
999.
The earthquake that occurred on May 24, 2013, in the basin of the Sea of Okhotsk with a magnitude of 8.3 was the strongest in this region. We have modeled a possible tsunami caused by such an earthquake. The simulations confirm that the wave heights were sufficiently small because the earthquake epicenter depth was 640 km. We analyze the oscillations of the DART buoys in the vicinity of the earthquake source and show that they were not associated with the tsunami waves. Analysis of the available pressure gauge records at different points of the Sea of Okhotsk show that only in one case (Iturup Island) can the observed oscillations of the sea level with a height of approximately 4 cm be classified as tsunami waves.  相似文献   
1000.
A brief analysis of the oceanographic papers printed in this issue is presented. For convenience of the reader, the paper by K. Bryan, a prominent scientist and expert in modeling the physical characteristics of the ocean, is discussed in detail. The remaining studies are described briefly in several sections: direct prognostic modeling, diagnosis–adaptation, four-dimensional analysis, and operational oceanography. At the end of the study, we separately discuss the problem of the reproduction of coastal intensification of temperature, salinity, density, and currents. We believe that the quality of the simulation results can be best assessed in terms of the intensity of coastal currents. In conclusion, this opinion is justified in detail.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号