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   3487篇
  免费   2篇
  国内免费   6篇
航空   1817篇
航天技术   991篇
综合类   5篇
航天   682篇
  2021年   13篇
  2019年   15篇
  2018年   171篇
  2017年   147篇
  2016年   58篇
  2015年   36篇
  2014年   50篇
  2013年   62篇
  2012年   88篇
  2011年   207篇
  2010年   185篇
  2009年   227篇
  2008年   236篇
  2007年   197篇
  2006年   47篇
  2005年   113篇
  2004年   84篇
  2003年   91篇
  2002年   46篇
  2001年   105篇
  2000年   45篇
  1999年   86篇
  1998年   85篇
  1997年   62篇
  1996年   63篇
  1995年   88篇
  1994年   97篇
  1993年   42篇
  1992年   61篇
  1991年   22篇
  1990年   28篇
  1989年   56篇
  1988年   20篇
  1987年   35篇
  1986年   19篇
  1985年   74篇
  1984年   42篇
  1983年   46篇
  1982年   55篇
  1981年   77篇
  1980年   26篇
  1979年   24篇
  1978年   22篇
  1977年   18篇
  1976年   15篇
  1975年   18篇
  1974年   12篇
  1972年   17篇
  1969年   13篇
  1966年   8篇
排序方式: 共有3495条查询结果,搜索用时 15 毫秒
131.
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   
132.
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   
133.
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   
134.
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   
135.
136.
The paper presents a technique of forming and evaluating the allowable clearance between a launch vehicle fairing and spacecraft.  相似文献   
137.
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   
138.
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   
139.
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   
140.
The paper discusses the applicability of cold gaseous nitrogen as a model working fluid in testing the hydrogen pump seals for power plants by three-dimensional modeling.  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