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   735篇
  免费   20篇
  国内免费   2篇
测绘学   13篇
大气科学   58篇
地球物理   173篇
地质学   288篇
海洋学   57篇
天文学   102篇
综合类   3篇
自然地理   63篇
  2021年   8篇
  2020年   7篇
  2018年   12篇
  2017年   8篇
  2016年   12篇
  2014年   17篇
  2013年   27篇
  2012年   21篇
  2011年   21篇
  2010年   15篇
  2009年   33篇
  2008年   29篇
  2007年   24篇
  2006年   34篇
  2005年   23篇
  2004年   24篇
  2003年   16篇
  2002年   22篇
  2001年   19篇
  2000年   10篇
  1999年   13篇
  1998年   11篇
  1997年   6篇
  1996年   8篇
  1995年   7篇
  1994年   8篇
  1993年   9篇
  1992年   7篇
  1991年   12篇
  1990年   7篇
  1989年   6篇
  1987年   7篇
  1985年   6篇
  1984年   9篇
  1983年   15篇
  1982年   11篇
  1981年   9篇
  1980年   8篇
  1977年   14篇
  1976年   9篇
  1975年   8篇
  1974年   8篇
  1973年   6篇
  1972年   11篇
  1970年   7篇
  1955年   7篇
  1954年   9篇
  1952年   6篇
  1950年   8篇
  1948年   8篇
排序方式: 共有757条查询结果,搜索用时 15 毫秒
91.
Abstract

In this study, the development of a moderate coastal storm with intense precipitation that occurred during 12–14 February 1993 is examined using a high‐resolution version of the Canadian Regional Finite‐element (RFE) model with more realistic physical representations. It is shown that the improved RFE model predicts well the coastal cyclogenesis events and also the distribution and intensity of heavy mixed precipitation (rain and snow) associated with the storm. It is found that the cyclogenesis takes place in response to the low‐level inshore advection of high‐θe air from the maritime boundary layer, and the approach of a mid‐level shortwave trough with a warm pool above that is previously associated with a decaying cyclone upstream. More rapid deepening of the cyclone ensues as intense precipitation falls along the warm and cold fronts near the cyclone centre.

Diagnosis of the control and sensitivity simulations reveals that the low‐level inshore warm advection and the propagation of the stratospheric warm pool contribute more significantly to the surface pressure falls during the incipient stage, whereas the mid‐level shortwave trough plays an important role in the cyclogenesis at later stages. Overall, latent heat release accounts for about 50% of the cyclone's total deepening, in agreement with the presence of a moderate baroclinic environment and the generation of intense precipitation.

The diabatic and kinematic structures near the rain‐snow boundary are examined to gain insight into the influence of melting snow on the cyclogenesis. It is shown that the improved RFE model reproduces well the rain‐snow boundary structures as previously observed. Moreover, a thermally indirect circulation (perturbation) can be seen in the vicinity of the rain‐snow boundary. It is found, however, that melting of snow tends to produce a weak negative or negligible impact on the cyclogenesis, as opposed to previous hypotheses.  相似文献   
92.
Ohne ZusammenfassungErweiterte Veröffentlichung des gleichnamigen Vortrags auf der Tagung der Geologischen Vereinigung, Frankfurt a. M., 9. Januar 1938.  相似文献   
93.
94.
95.
We investigate the dependence of the strength of galaxy clustering on intrinsic luminosity using the Anglo-Australian two degree field galaxy redshift survey (2dFGRS). The 2dFGRS is over an order of magnitude larger than previous redshift surveys used to address this issue. We measure the projected two-point correlation function of galaxies in a series of volume-limited samples. The projected correlation function is free from any distortion of the clustering pattern induced by peculiar motions and is well described by a power law in pair separation over the range     . The clustering of     galaxies in real space is well-fitted by a correlation length     and power-law slope     . The clustering amplitude increases slowly with absolute magnitude for galaxies fainter than M *, but rises more strongly at higher luminosities. At low luminosities, our results agree with measurements from the Southern Sky Redshift Survey 2 by Benoist et al. However, we find a weaker dependence of clustering strength on luminosity at the highest luminosities. The correlation function amplitude increases by a factor of 4.0 between     and −22.5, and the most luminous galaxies are 3.0 times more strongly clustered than L * galaxies. The power-law slope of the correlation function shows remarkably little variation for samples spanning a factor of 20 in luminosity. Our measurements are in very good agreement with the predictions of the hierarchical galaxy formation models of Benson et al.  相似文献   
96.
A review has been undertaken of all available information on crustal stresses in Norwegian continental shelf and North Sea. The data have principally come from the results of borehole breakouts, supplemented by focal mechanisms. A simple model of a soft linear inclusion was developed to explain the rapid changes in stress orientation in the Central Graben area. This example indicates that the stress field is affected locally by the geological or structural environment.  相似文献   
97.
98.
We present the results of a radial velocity (RV) survey of 46 subdwarf B (sdB) and 23 helium-rich subdwarf O (He-sdO) stars. We detected 18 (39%) new sdB binary systems, but only one (4%) He-sdO binary. Orbital parameters of nine sdB and sdO binaries, derived from follow-up spectroscopy, are presented. Our results are compared with evolutionary scenarios and previous observational investigations.  相似文献   
99.
100.
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