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   7044篇
  免费   633篇
  国内免费   177篇
测绘学   281篇
大气科学   762篇
地球物理   2390篇
地质学   2794篇
海洋学   525篇
天文学   557篇
综合类   195篇
自然地理   350篇
  2023年   12篇
  2022年   42篇
  2021年   62篇
  2020年   58篇
  2019年   62篇
  2018年   509篇
  2017年   434篇
  2016年   356篇
  2015年   226篇
  2014年   192篇
  2013年   246篇
  2012年   735篇
  2011年   539篇
  2010年   227篇
  2009年   244篇
  2008年   243篇
  2007年   193篇
  2006年   205篇
  2005年   887篇
  2004年   935篇
  2003年   699篇
  2002年   215篇
  2001年   104篇
  2000年   65篇
  1999年   35篇
  1998年   29篇
  1997年   36篇
  1996年   25篇
  1995年   23篇
  1994年   6篇
  1993年   9篇
  1992年   7篇
  1991年   15篇
  1990年   21篇
  1989年   12篇
  1987年   9篇
  1986年   6篇
  1985年   10篇
  1984年   12篇
  1983年   8篇
  1982年   8篇
  1981年   5篇
  1980年   7篇
  1978年   5篇
  1977年   5篇
  1975年   7篇
  1973年   4篇
  1972年   4篇
  1956年   4篇
  1954年   4篇
排序方式: 共有7854条查询结果,搜索用时 390 毫秒
331.
The influences of human activities on regional climate and weather are tremendous. The re-gional temperature and the distributing of wind field are influenced, whereas the precipitation in-tensity and the spatial and temporal distribution of the precipita…  相似文献   
332.
Basic characteristics of active tectonics of China   总被引:84,自引:8,他引:76  
Active tectonics is inferred to all the structures which have been active since the late Pleisto-cene, 100—120 ka B.P., are still active recently, and will be active in a certain time period in the future, such as active faults, active folds, active basi…  相似文献   
333.
To develop geosciences quantification and multi-dimensional researches will be an inevitable trend in the 21st century. The interaction between the land surface and the atmosphere not only serves as an important component in geosciences quantification, bu…  相似文献   
334.
When organic matter during geological processes is affected by a variety of factors such as paleotemperature, and time, complicated chemical reactions will occur, finally resulting in the generation of petroleum and natural gas. These reactions leading to…  相似文献   
335.
Evolution mechanism of the western Pacific subtropical high   总被引:4,自引:0,他引:4  
Ever since Charney et al.[1] studied the multiple equilibrium states in atmosphere with highly truncated spectral method in 1979, many Chinese researchers, such as Li Maicun et al. (1983)[2], Liu Chongjian et al. (1983)[3], Miu Jinhai et al. (1985)[4] and…  相似文献   
336.
The generation of natural gases is much more complicated in comparison with liquid petro-leum in that natural gases could be generated from both humic and sapropelic organic matter at different stages and that natural gases could be organic and inorganic …  相似文献   
337.
From the latest Precambrian to the Early Cambrian was the most important phase throughout the evolutionary history of life on the earth. The diversification of latest Precambrian multicellular organisms was obvious and some of them began to form primary s…  相似文献   
338.
Since the 1970s, environmental magnetism has found extensive applications in diverse research areas of geoscience[1]. In China, a lot of environmental magnetic studies have been carried out on loess, lake and marine sediments for the purpose of paleoclima…  相似文献   
339.
The processes and rates of the weathering denudation of the bare crystalline rock are important problems in the field of geosciences[1—6]. Essentially, the weathering denudation process is the process of rock destruction and transportation. In different …  相似文献   
340.
A dating of two biotite samples taken from the meso- and low-temperature mylonites within the Shangyi-Chicheng fault belt on the north of the North China Craton yields 40Ar/39Ar isotopic ages of (399 ± 1) Ma and (263 ± 2) Ma, respectively. These data reflect an Early Devonian deformation and a Late Carboniferous retrograde metamorphism event along the fault, suggesting that the tectonic activities of the North China Craton in Paleozoic should be reconsidered.  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