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   3277篇
  免费   10篇
  国内免费   10篇
航空   1696篇
航天技术   815篇
综合类   10篇
航天   776篇
  2021年   22篇
  2018年   170篇
  2017年   147篇
  2016年   57篇
  2015年   33篇
  2014年   49篇
  2013年   58篇
  2012年   87篇
  2011年   216篇
  2010年   184篇
  2009年   216篇
  2008年   186篇
  2007年   184篇
  2006年   45篇
  2005年   111篇
  2004年   85篇
  2003年   72篇
  2002年   37篇
  2001年   60篇
  2000年   39篇
  1999年   47篇
  1998年   67篇
  1997年   43篇
  1996年   67篇
  1995年   79篇
  1994年   55篇
  1993年   53篇
  1992年   65篇
  1991年   30篇
  1990年   19篇
  1989年   49篇
  1988年   23篇
  1987年   20篇
  1986年   21篇
  1985年   83篇
  1984年   53篇
  1983年   53篇
  1982年   60篇
  1981年   72篇
  1980年   21篇
  1979年   26篇
  1978年   26篇
  1977年   26篇
  1976年   20篇
  1975年   20篇
  1974年   20篇
  1973年   11篇
  1972年   14篇
  1970年   18篇
  1969年   19篇
排序方式: 共有3297条查询结果,搜索用时 15 毫秒
151.
The bearing capacity of hybrid segmented bearings with different groove systems is compared. The research establishes that the system with a crescent groove has the best characteristics.  相似文献   
152.
The DB-8 detectors of the ISS radiation monitoring system (RMS) have operated almost continuously onboard the ISS service module since August 2001 till December 2014. The RMS data obtained were used for the daily monitoring of the radiation environment aboard the station. This paper considers the technique of RMS data analysis that allows one to distinguish the contributions of galactic cosmic rays and the Earth’s inner radiation belt to the daily dose based on the dosimetry data obtained as a result of the station’s passage in areas of the highest geomagnetic latitudes. The paper presents the results of an analysis of the dosimetry data based on this technique for 2005–2011, as well as a comparison with similar results the authors obtained previously using the technique based on an analysis of the dosimetry data obtained during station passages in the area of the South Atlantic Anomaly.  相似文献   
153.
154.
155.
156.
Space Science Reviews - Time measured by an ideal clock crucially depends on the gravitational potential and velocity of the clock according to general relativity. Technological advances in...  相似文献   
157.
A method of determining the maximum permissible values for diagnostic signs, being an integral part of health and usage monitoring systems (HUMS) of the helicopter transmission units, has been developed based on a probabilistic approach.  相似文献   
158.
Plasma of the free burning electric arc between Ag–SnO2–ZnO composite electrodes as well as brass electrodes were investigated. The plasma temperature distributions were obtained by Boltzmann plot method involving Cu I, Ag I or Zn I spectral line emissions. The electron density distributions were obtained from the width and from absolute intensity of spectral lines. The laser absorption spectroscopy was used for measurement of copper atom concentration in plasma. Plasma equilibrium composition was calculated using two independent groups of experimental values (temperature and copper atom concentration, temperature and electron density). It was found that plasma of the free burning electric arc between brass electrodes is in local thermodynamical equilibrium. The experimental verification of the spectroscopic data of Zn I spectral lines was carried out.  相似文献   
159.
Based on an integrated approach, we solve the optimization problem for energy content and weight-dimensional characteristics of the electric servo drive by synthesis of structure and analysis of characteristics for different power supplies. The generalized power supply model, developed for different power supply of drive control systems, is given.  相似文献   
160.
The problem and features of measuring the speed and the direction angle of the wind vector relative to the longitudinal helicopter axis during parking, starting and takeoff-landing modes by onboard means are considered. The construction principles, information processing algorithms and advantages of onboard system for measuring the wind vector parameters based on ion-beacon and aerometric measuring channels, are disclosed.  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