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   287篇
  免费   3篇
  国内免费   5篇
航空   212篇
航天技术   14篇
航天   69篇
  2024年   1篇
  2022年   2篇
  2021年   5篇
  2020年   3篇
  2019年   3篇
  2018年   25篇
  2017年   19篇
  2016年   21篇
  2015年   12篇
  2014年   19篇
  2013年   28篇
  2012年   26篇
  2011年   19篇
  2010年   20篇
  2009年   20篇
  2008年   23篇
  2007年   23篇
  2006年   7篇
  2005年   9篇
  2004年   4篇
  2003年   1篇
  2001年   2篇
  1994年   1篇
  1988年   1篇
  1985年   1篇
排序方式: 共有295条查询结果,搜索用时 15 毫秒
71.
The results of shaping process were obtained by the process scheme of serial stretching for biconvex skin of workpieces using the ANSYS/LS-DYNA software. The analysis is based on different flow material characteristics during plastic deformation at solid friction. A statistical analysis of the calculation results for disturbing factors assessment is carried out.  相似文献   
72.
Theoretical and experimental methods of investigating the performance of an electric actuator of maneuverable unmanned aerial vehicle (UAV) is considered in order to solve the aeroelasticity tasks. Models of the stability analysis for the rudder–actuator system as well as the examples of numerical and experimental studies of this system performance are given.  相似文献   
73.
The equations of the mathematical model are solved in terms of special functions. The results for the design scheme of the aircraft forebody are obtained with a guaranteed accuracy by the stable method of functional normalization.  相似文献   
74.
We consider a probabilistic estimation of microaccelerations being produced in the inboard environment of an orbital laboratory as a random process; based on this estimation we analyzed a probability of fulfilling the favorable conditions to realize gravity-sensitive processes. The approach suggested can be applied when designing a space laboratory to meet the requirements for the microaccelerations inside the working zone of technological equipment.  相似文献   
75.
A technique is suggested for calculating the helicopter spatial motion and the stress-strain state of a skid landing gear in the course of landing with regard for the second landing impact; geometric, material and design nonlinearity of undercarriage springs deformation is taken into account. The comparison between the analysis results and experimental data is presented.  相似文献   
76.
77.
The investigation of stability and precision of the previously proposed implicit scheme of direct integration for the finite element equations of motion is presented. The scheme parameter values that ensure its unconditional stability in the nonlinear problems are determined and comparison with existing procedures is given.  相似文献   
78.
Variations in concentration of ions H+, He+, and O+ are studied at a height of about 700 km using the data of continuous observations onboard the DEMETER satellite at the decline and in the minimum of solar activity from 2004 to 2008. Latitudinal distributions, seasonal behavior, and irregular variations in ion concentrations and their dependence on solar and geomagnetic activity are considered. Within this altitude range, for the first time an analysis is performed of the dataset of many-year continuous observations in both hemispheres from the equatorial to subauroral latitudes. This made it possible to describe the seasonal and irregular variations of the concentrations of main ion species with better time and spatial resolution than in the available empirical models. The dependence of concentrations of three types of ions on solar and geomagnetic activity is studied at time scales from several days to several years, and it is shown that the anti-phase change in concentrations of O+ and light ions known from publications is partly a result of mutual dependence of solar and geomagnetic activity and is observed only at time scales beginning from several months. At time scales from several days to several weeks, variations in the concentration of O+ and light ions are governed mainly by solar and geomagnetic activity, respectively.  相似文献   
79.
In this paper, the existing techniques of electrochemical dimensional machining are considered. The use of an additional current-conducting template makes it possible to improve the accuracy of materials separation with the aid of the electric field superimposed.  相似文献   
80.
Making use of the Weierstrass-Mandelbrot fractal function, some problems connected with the adequate assessment of microaccelerations aboard a spacecraft are considered. The ranges of values for the function parameters that make it possible to simulate the quasi-static component of microaccelerations are also determined.  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