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   5293篇
  免费   6篇
  国内免费   8篇
航空   2775篇
航天技术   1642篇
综合类   18篇
航天   872篇
  2018年   180篇
  2017年   151篇
  2016年   66篇
  2015年   39篇
  2014年   66篇
  2013年   92篇
  2012年   112篇
  2011年   250篇
  2010年   212篇
  2009年   270篇
  2008年   315篇
  2007年   215篇
  2006年   73篇
  2005年   150篇
  2004年   138篇
  2003年   153篇
  2002年   79篇
  2001年   150篇
  2000年   89篇
  1999年   109篇
  1998年   141篇
  1997年   101篇
  1996年   114篇
  1995年   140篇
  1994年   165篇
  1993年   86篇
  1992年   118篇
  1991年   49篇
  1990年   58篇
  1989年   116篇
  1988年   40篇
  1987年   56篇
  1986年   63篇
  1985年   143篇
  1984年   88篇
  1983年   97篇
  1982年   105篇
  1981年   134篇
  1980年   56篇
  1979年   46篇
  1978年   42篇
  1977年   38篇
  1976年   26篇
  1975年   40篇
  1974年   36篇
  1973年   32篇
  1972年   36篇
  1971年   35篇
  1969年   35篇
  1966年   26篇
排序方式: 共有5307条查询结果,搜索用时 15 毫秒
211.
A technique of analyzing the flutter initiation in flat plate compressor cascades was developed. The viscous and inviscid flow study was carried out using the COBRA solver based on the modified implicit Godunov method and unsteady implicit method updated for using. The flutter conditions were revealed and the effect of taking into account viscosity, angles of attack and time steps was investigated.  相似文献   
212.
The influence of the clearance between the case and blade ends of the semi-open impeller on the centrifugal stage characteristics is considered using the experimental data and numerical calculation results.  相似文献   
213.
The influence of geometry and operating conditions of the centrifugal compressor stage on the radial gas force is determined on the basis of the theoretical method and calculation program using experimental boundary conditions.  相似文献   
214.
The application of the low dissipative high-order accurate scheme for numerical solution of the Euler and Navier-Stokes equations in the two-dimensional statement is considered. The scheme of calculating space derivatives is the seven-point central-difference approximation of the fourth order with the coefficients optimized to reduce the dispersion errors. The optimized six-step Runge-Kutta method is used for evaluating the time derivatives. By means of filtration, spurious pulsations are suppressed and shocks are processed. The results of verifying the calculation scheme realized on the stationary problem of flow around the model turbine blades are presented.  相似文献   
215.
A mathematical model of the process of bending and rolling the thin-walled components is presented taking into account the geometrical nonlinearity. Also presented is the technique for calculating the setup variables of bending equipment, which is based on reduction of the initial differential boundary-value problem to the discrete one with the use of the finite difference method.  相似文献   
216.
217.
The paper presents a technique of forming and evaluating the allowable clearance between a launch vehicle fairing and spacecraft.  相似文献   
218.
This paper deals with the technical features of designing an information-controlling system to prevent critical operating conditions of the helicopter flight, a technique for evaluating its effectiveness, analysis and synthesis of the measurement channels, forming of warning signals, and information support of the crew in abnormal situations.  相似文献   
219.
We determine the behavior of onboard gas-generator flowrate for generating the cavitation flow around a hybrid aerial underwater vehicle by using an annular wing on the underwater trajectory section.  相似文献   
220.
Junocam is a wide-angle camera designed to capture the unique polar perspective of Jupiter offered by Juno’s polar orbit. Junocam’s four-color images include the best spatial resolution ever acquired of Jupiter’s cloudtops. Junocam will look for convective clouds and lightning in thunderstorms and derive the heights of the clouds. Junocam will support Juno’s radiometer experiment by identifying any unusual atmospheric conditions such as hotspots. Junocam is on the spacecraft explicitly to reach out to the public and share the excitement of space exploration. The public is an essential part of our virtual team: amateur astronomers will supply ground-based images for use in planning, the public will weigh in on which images to acquire, and the amateur image processing community will help process the data.  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