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   424篇
  免费   25篇
  国内免费   4篇
测绘学   4篇
大气科学   30篇
地球物理   101篇
地质学   183篇
海洋学   14篇
天文学   102篇
自然地理   19篇
  2020年   5篇
  2019年   5篇
  2018年   6篇
  2017年   6篇
  2016年   15篇
  2015年   15篇
  2014年   16篇
  2013年   18篇
  2012年   15篇
  2011年   23篇
  2010年   21篇
  2009年   20篇
  2008年   15篇
  2007年   13篇
  2006年   11篇
  2005年   6篇
  2004年   18篇
  2003年   8篇
  2002年   14篇
  2001年   13篇
  2000年   10篇
  1999年   7篇
  1998年   5篇
  1997年   5篇
  1996年   6篇
  1995年   4篇
  1994年   5篇
  1993年   7篇
  1992年   3篇
  1991年   3篇
  1990年   4篇
  1989年   3篇
  1988年   4篇
  1986年   5篇
  1985年   10篇
  1984年   15篇
  1983年   8篇
  1982年   5篇
  1980年   12篇
  1979年   4篇
  1977年   5篇
  1976年   5篇
  1975年   8篇
  1974年   5篇
  1973年   3篇
  1971年   5篇
  1970年   4篇
  1967年   4篇
  1964年   3篇
  1962年   4篇
排序方式: 共有453条查询结果,搜索用时 0 毫秒
451.
452.
Subduction zones of continental, transitional, and oceanic settings, relative to the nature of the overriding plate, are compared in terms of trace element compositions of mafic to intermediate arc rocks, in order to evaluate the relationship between subduction parameters and the presence of subduction fluids. The continental Chilean Southern Volcanic Zone (SVZ) and the transitional to oceanic Central American Volcanic Arc (CAVA) show increasing degrees of melting with increasing involvement of slab fluids, as is typical for hydrous flux melting beneath arc volcanoes. At the SVZ, the central segment with the thinnest continental crust/lithosphere erupted the highest-degree melts from the most depleted sources, similar to the oceanic-like Nicaraguan segment of the CAVA. The northern part of the SVZ, located on the thickest continental crust/lithosphere, exhibits features more similar to Costa Rica situated on the Caribbean Large Igneous Province, with lower degrees of melting from more enriched source materials. The composition of the slab fluids is characteristic for each arc system, with a particularly pronounced enrichment in Pb at the SVZ and in Ba at the CAVA. A direct compositional relationship between the arc rocks and the corresponding marine sediments that are subducted at the trenches clearly shows that the compositional signature of the lavas erupted in the different arcs carries an inherited signal from the subducted sediments.  相似文献   
453.
A series of triaxial compression tests, triaxial extension tests, and triaxial compression creep tests were conducted to evaluate the strength, deformability, and permeability of rock salt from the Jintan location. Based on a previous analysis, the measured data can be physically modeled very well as shown by the constitutive model Hou/Lux and indicate that China’s representative bedded rock salt from the Jintan location is characterized by good ductility and deformation properties, similar to the European high-purity rock salt. Based on a comparison of compression as well as extension failure strength determined at rock salt from Jintan location, a similarity of compression and extension failure strength could be demonstrated. Permeation flow seems to be an anisotropic process because the permeability measured at samples prior to failure by compression tests differs to those measured at samples prior to failure by extension tests. The anisotropy of damage and destruction of rock salt has a significant influence on permeability. In case of triaxial compression tests, the measured permeability increases two to six orders of magnitude because of consistent direction of injection and cracks. In case of triaxial extension tests, however, the permeability increases less with a maximum of two orders in magnitude. The test results are significant for understanding the load-bearing behavior of rock salt from Jintan location and investigations with reference to the stability and tightness of underground caverns.  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