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   4860篇
  免费   25篇
  国内免费   19篇
航空   2150篇
航天技术   1689篇
综合类   11篇
航天   1054篇
  2021年   42篇
  2019年   27篇
  2018年   112篇
  2017年   94篇
  2016年   82篇
  2015年   43篇
  2014年   117篇
  2013年   137篇
  2012年   129篇
  2011年   193篇
  2010年   144篇
  2009年   229篇
  2008年   256篇
  2007年   155篇
  2006年   112篇
  2005年   142篇
  2004年   139篇
  2003年   166篇
  2002年   112篇
  2001年   180篇
  2000年   94篇
  1999年   96篇
  1998年   117篇
  1997年   84篇
  1996年   128篇
  1995年   145篇
  1994年   135篇
  1993年   64篇
  1992年   100篇
  1991年   43篇
  1990年   43篇
  1989年   101篇
  1988年   39篇
  1987年   39篇
  1986年   49篇
  1985年   139篇
  1984年   117篇
  1983年   82篇
  1982年   96篇
  1981年   148篇
  1980年   32篇
  1979年   30篇
  1978年   33篇
  1977年   36篇
  1976年   23篇
  1975年   39篇
  1974年   35篇
  1973年   28篇
  1970年   22篇
  1969年   22篇
排序方式: 共有4904条查询结果,搜索用时 46 毫秒
221.
222.
223.
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   
224.
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   
225.
We consider the stability of stationary motions of a model of a spacecraft as a system of coaxial bodies with small asymmetry caused by the shift of the axes of dynamic symmetry of bodies relative to the axis of rotation. We determine the stationary motions of the system; their stability is studied with respect to both the projections of angular velocity and the position of the axis of rotation. The sufficient conditions for the stability of these stationary motions are obtained by constructing a Lyapunov function, and the necessary conditions are obtained by analyzing the corresponding linearized equations of perturbed motion.  相似文献   
226.
This paper presents the results of analyzing the shaping of thin-walled conical parts with the uniform thickness along generatrix.  相似文献   
227.
228.
The discretization of the boundary value problem for laminated composite shells is based on the finite difference approach using the regular mesh with the constant grid step and the difference operators of the second order of accuracy. The dynamic relaxation method is proposed for the solution of the nonlinear problem. The evolutionary equations of the dynamic relaxation are constructed, and the optimum parameters of the converging linear iterative process are estimated.  相似文献   
229.
A problem of modeling the incompressible viscous flow between two disks taking into account the rotation of one of them is considered. We study the effect of the disk angular velocity (flow regimes) in the interdisk spacing, finiteness (infiniteness) of disk radiuses, calculation region configuration as well as distances between disks on the flow characteristics, particularly, on the resistance moment coefficient. Numerical simulation is performed with the aid of Maple and ANSYS Fluent software.  相似文献   
230.
We consider the peculiarities of application for the cabin indicating systems of secondary information display, formulate and systematize the compositional and technical requirements for display systems and their elements. The tendencies and lines in the development of head-up displays for avionics and autobasing complexes were determined. The technique of calculating optics of such display systems with the use of electronic distortion compensation is presented.  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