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   251167篇
  免费   5189篇
  国内免费   3238篇
测绘学   6930篇
大气科学   18964篇
地球物理   52255篇
地质学   86871篇
海洋学   21169篇
天文学   54502篇
综合类   990篇
自然地理   17913篇
  2021年   2157篇
  2020年   2574篇
  2019年   2819篇
  2018年   3333篇
  2017年   3004篇
  2016年   5601篇
  2015年   4187篇
  2014年   6900篇
  2013年   14205篇
  2012年   6403篇
  2011年   7641篇
  2010年   6679篇
  2009年   9336篇
  2008年   8212篇
  2007年   7626篇
  2006年   9622篇
  2005年   7657篇
  2004年   7595篇
  2003年   7032篇
  2002年   6591篇
  2001年   5879篇
  2000年   5557篇
  1999年   4810篇
  1998年   4845篇
  1997年   4634篇
  1996年   4215篇
  1995年   4311篇
  1994年   4001篇
  1993年   3742篇
  1992年   3500篇
  1991年   3526篇
  1990年   3624篇
  1989年   3332篇
  1988年   3169篇
  1987年   3708篇
  1986年   3251篇
  1985年   4121篇
  1984年   4633篇
  1983年   4307篇
  1982年   4231篇
  1981年   3851篇
  1980年   3602篇
  1979年   3436篇
  1978年   3439篇
  1977年   3223篇
  1976年   2967篇
  1975年   2902篇
  1974年   2865篇
  1973年   3057篇
  1972年   1989篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Emelyanov  N. V. 《Astronomy Reports》2018,62(12):977-985

There is wide interest in the results of studies of the dynamics of satellites of planets. Such data are needed to determine the physical properties of celestial bodies, and they may be able to provide information about the origins and evolution of the solar system. The general approach to studying the dynamics of satellites involves developing models for the motion and ephemerides based on observational data. Ephemerides are required to prepare and launch space missions to other planets and help discover new celestial bodies. High-precision astrometric coordinates of the principal satellites of Jupiter, Saturn, and Uranus are derived from photometric observations of occultations and eclipses of these satellites. To this end, worldwide observing campaigns have been organized. Enhancement in the precision of ephemerides can be obtained not only by increasing the accuracy of observations, but also by expanding the time interval covered by the observations. Many new, distant satellites of the major planets were discovered in the early 21st century. However, observations of these satellites are scarce and were obtained over short time intervals; as a result, some of these satellites were lost. To date, 179 natural satellites are known. This paper is based on a presentation made at the conference “Modern Astrometry 2017,” dedicated to the memory of K.V. Kuimov (Sternberg Astronomical Institute, Moscow State University, October 23–25, 2017).

  相似文献   
992.
Milyukov  V. K.  Yeh  Hsien-Chi 《Astronomy Reports》2018,62(12):1003-1012
Astronomy Reports - A review of the achievements of space geodesy in the 21st century, represented by the successful realization of the CHAMP, GOCE, and GRACE missions, is presented. The main...  相似文献   
993.
Sazhin  M. V.  Zharov  V. E.  Kalinina  T. A.  Sementsov  V. N. 《Astronomy Reports》2018,62(12):1026-1029
Astronomy Reports - It has recently become clear that the potential role of astrometry in cosmological studies has been underestimated. Some areas of cosmology that should be investigated using...  相似文献   
994.
Doklady Earth Sciences - Ways of combined usage of data obtained by the satellite sounding of the marine surface along with modeling approaches are considered. The technique of data application is...  相似文献   
995.
Doklady Earth Sciences - This paper reports on the results of the seismic studies on the disastrous water-stone flow passing down the Kyngarga River (Republic of Buryatia) on June 27–29,...  相似文献   
996.
Demidova  T. A.  Morozov  E. G.  Neiman  V. G. 《Doklady Earth Sciences》2018,482(1):1229-1233

The velocity and structure of the Lomonosov Equatorial Undercurrent of the Atlantic Ocean are determined based on the data measured with a shipborne acoustic profiler from 2014 to 2017. The seasonal variability of this flow is estimated, and the cases of its outcropping to the surface in the spring of the Northern Hemisphere are revealed.

  相似文献   
997.
Fishchenko  V. K.  Dolgikh  G. I.  Zimin  P. S.  Subote  A. E. 《Doklady Earth Sciences》2018,482(1):1244-1247

The design features of an oceanological video-monitoring system created for operational research of coastal infrasonic wave processes are described. The results obtained confirm great opportunities for its use in fundamental and applied works in various seasons. The processing of the obtained experimental data has revealed the dynamics of the wave processes starting from wind waves to diurnal tides.

  相似文献   
998.
Moroz  Yu. F.  Loginov  V. A. 《Doklady Earth Sciences》2018,482(2):1370-1374

The methods and results of magnetotelluric sounding in the range of 0.0001–1000 s and more with the use small portable magnetotelluric stations are considered. Data on the distribution of electrical conductivity at depths beneath the Avacha–Koryak zone of contemporary volcanism are obtained. The obtained data are interpreted using the modern techniques and methods.

  相似文献   
999.
Gladyshev  S. V.  Gladyshev  V. S.  Gulev  S. K.  Sokov  A. V. 《Doklady Earth Sciences》2018,483(2):1524-1527
Doklady Earth Sciences - The vertical structure and interannual and long-term variability of the meridional overturning circulation in the North Atlantic Subpolar Gyre is analyzed. A close...  相似文献   
1000.
Kalmykov  N. P.  Budaev  R. Ts. 《Doklady Earth Sciences》2018,483(2):1487-1490
Doklady Earth Sciences - Based on geochronological data, it is shown that the formation of sediments of a 50–80 m terrace of Lake Baikal occurred during the Middle Pleistocene and its top...  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