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   408篇
  免费   17篇
  国内免费   28篇
测绘学   4篇
大气科学   49篇
地球物理   76篇
地质学   141篇
海洋学   22篇
天文学   131篇
综合类   10篇
自然地理   20篇
  2023年   4篇
  2022年   3篇
  2021年   10篇
  2020年   16篇
  2019年   11篇
  2018年   17篇
  2017年   24篇
  2016年   24篇
  2015年   10篇
  2014年   13篇
  2013年   23篇
  2012年   15篇
  2011年   32篇
  2010年   31篇
  2009年   27篇
  2008年   10篇
  2007年   9篇
  2006年   15篇
  2005年   6篇
  2004年   5篇
  2003年   3篇
  2002年   6篇
  1999年   5篇
  1998年   7篇
  1997年   6篇
  1996年   4篇
  1995年   8篇
  1994年   4篇
  1993年   7篇
  1992年   3篇
  1991年   8篇
  1990年   10篇
  1989年   4篇
  1988年   5篇
  1987年   4篇
  1986年   4篇
  1984年   7篇
  1983年   10篇
  1982年   5篇
  1981年   6篇
  1980年   2篇
  1977年   5篇
  1976年   2篇
  1974年   4篇
  1973年   4篇
  1972年   4篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1965年   1篇
排序方式: 共有453条查询结果,搜索用时 0 毫秒
121.
A new formula is derived for the mass of spherically symmetric stellar configurations. An expression will be given where the mass square is connected to an integral over the pressure of gravitating matter. This formula turns out to hold for Newtonian gravity, for Einstein's GRT, for projective and bimetric scalar-tensor and further theories of gravitation.  相似文献   
122.
From 1988 to 1989 radial velocities of 76 components of 46 Trapzium-type multiple systems have been measured with the 125-cm reflector of the Abastumani Astrophysical Observatory. In Table 1 a list of observations is given, containing the mean values of radial velocities, velocities of axial rotation, the halfwidth of contours and equivalent width.  相似文献   
123.
虾壳红色素的抗氧化和抗肿瘤作用   总被引:8,自引:0,他引:8  
为综合利用虾、蟹等水产品壳废料,采用有机溶剂萃取方法提取虾壳中的红色素,它是一类以虾青素及其酯为主的类胡萝卜素。比较虾壳红色素与维生素C在抑制小鼠肝匀浆脂质过氧化,以及抑制人大肠癌SW1116细胞株增殖的作用。结果表明虾壳红色素对小鼠肝匀浆脂质过氧化具有明显的抑制作用,其效果比维生素C强10倍以上;浓度为1×10-9及1×10-8mol/L虾壳红色素对人大肠癌SW1116细胞株增殖抑制率分别为23.4%和39.0%,在浓度为1×10-7mol/L中培养的细胞基本死亡。提示了虾、蟹壳废料潜在的应用价值。  相似文献   
124.
Geomagnetism and Aeronomy - Photographic and video observations made by astronaut Thomas Pesquet (European Space Agency) during the 51st expedition to the International Space Station (ISS) contain...  相似文献   
125.
The effect of abiotic and biotic factors on the properties of nano-size particles in freshwater bodies is considered. Field studies of the aquatic environments of Lake Ladoga ecosystem provided an experimental confirmation of the total water mineralization and organic matter content in the formation of nano-size particle properties under natural conditions.  相似文献   
126.
In this paper, unusual optical phenomena observed in our country and abroad upon launches of Russian rockets are discussed and interpreted: they are regarded as the aftereffects of sunlight scattering by gas-dust clouds created by rocket fuel combustion products in different modes of engine operation. The results of instrumental observations of the clouds can be used to study physical processes in the upper atmosphere.  相似文献   
127.
Various mechanisms of the formation of AlO molecules during the operation of solid-propellant rocket engines in the upper atmosphere and processes of AlO glow decay are considered. The main contribution to AlO formation at altitudes of 120–200 km is made by the interaction of metallic aluminum contained in products of solid propellant combustion with atmospheric oxygen. The decrease in the brightness of AlO clouds is caused by a decrease in the AlO concentration as a result of cloud expansion due to diffusion processes and AlO oxidation with atomic oxygen.  相似文献   
128.
Izvestiya, Physics of the Solid Earth - In the research aimed at determining tectonic stresses from fault-slip data (the seismological data on the focal mechanisms of earthquakes, geological data...  相似文献   
129.
Archeological, archeoseismological, and seismotectonic studies were carried out in Salachik, the ancient capital of the Crimean Khans, on the outskirts of the modern city of Bakhchysarai, Crimea. The following damage and deformations of medieval buildings were observed: tilted building walls, shifted elements of building structures, rotation of fragments of walls and building blocks around the vertical axis, considerable deformations of arch structures, and fissures running through several rows of building blocks. These deformations are of a seismogenic nature. Traces of at least two strong ancient earthquakes were revealed in the medieval monuments of Salachik. Based on analysis of kinematic indicators, it is found that the maximum seismic intensity (VIII ≤ I 0 ≤ IX points) was due to an earthquake occurred in the west. Based on historical seismologic data, one of the two earthquakes is dated by April 30, 1698. Also, structural damage to buildings in Salachik was caused by Crimean earthquakes in 1927. The findings can be used for a comprehensive assessment of seismic hazards on the Crimean Peninsula.  相似文献   
130.
Water Resources - Estimate is made for the possible reduction of nutrient export from the drainage basins of tributaries of the Kuibyshev Reservoir through the introduction of the best available...  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