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   36篇
  免费   7篇
  国内免费   24篇
航空   52篇
航天技术   7篇
航天   8篇
  2024年   2篇
  2023年   8篇
  2022年   17篇
  2020年   3篇
  2019年   1篇
  2018年   2篇
  2016年   4篇
  2015年   1篇
  2008年   2篇
  2007年   1篇
  2006年   5篇
  2005年   1篇
  2001年   1篇
  2000年   1篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1995年   3篇
  1994年   2篇
  1993年   4篇
  1992年   3篇
  1990年   1篇
  1987年   1篇
排序方式: 共有67条查询结果,搜索用时 46 毫秒
21.
The development of Chinese manned space engineering has a great role in promoting the progress of Chinese space medicine. With the accelerated implementation of Chinese Space Station Program, China's space medicine has made fruitful achievements over the past three years. This report summarizes the major progress of Chinese space medicine in terms of basic research and space applications from 2016 to 2018.   相似文献   
22.
23.
Using hydrous aluminum chloride (AlCl3·6H2O) and silicon ethoxide (Si (OC2H5)4) as raw materials, a kind of nano-sized mullite powder was synthesized with the sol-gel process at the medium calcination temperature. The microstructures of the alumina-silica binary aerogel and calcined nano-sized materials were investigated by means of thermogravimetry-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and X-ray diffractometer (XRD). The results show that the mullitization of Al2O3-SiO2 in gel starts from about 1 000 ℃ and its formation of mullite takes place in the range of 1 100 ℃-1 250 ℃. The size of the nano-sized mullite pow-der calcined at 1 250 ℃ is measured to be about 30 nm.  相似文献   
24.
The Solar Polar ORbit Telescope (SPORT) project for space weather mission has been under intensive scientific and engineering background studies since it was incorporated into the Chinese Space Science Strategic Pioneer Project in 2011.SPORT is designed to carry a suite of remote-sensing and in-situ instruments to observe Coronal Mass Ejections (CMEs),energetic particles,solar high-latitude magnetism,and the fast solar wind from a polar orbit around the Sun. The first extended view of the polar regions of the Sun and the ecliptic enabled by SPORT will provide a unique opportunity to study CME propagation through the inner heliosphere,and the solar high-latitude magnetism giving rise to eruptions and the fast solar wind.Coordinated observations between SPORT and other spaceborne/ground-based facilities within the International Living With a Star (ILWS) framework can significantly enhance scientific output.SPORT is now competing for official selection and implementation during China's 13th Five-Year Plan period of 2016-2020.   相似文献   
25.
某型飞机进气道测量耙研制   总被引:6,自引:1,他引:5  
由于某型飞机设计定型试飞的需要,需在进气道流场中设计一个装有压力或温度传感器的参数测量装置(以下简称测量耙)。由于安装环境的特殊性,其结构设计的难度和要求是空前的。本文对该测量耙的设计条件和创新结构作了详细的叙述。该测量耙通过强度计算和振动试验考核后,最终获许装机使用,并顺利完成某型飞机设计定型试飞的测试任务。在其它型号飞机的试飞中,该进气道测量耙的结构设计也得到了广泛使用。  相似文献   
26.
27.
At the 6th China Satellite Navigation Conference,CSNC 2015,a wide range of activities,such as highend forums,academic exchanges,an exhibition,as well as popularization of science were arranged.Over 2000 attendants including officials from departments in charge of navigation satellite systems,experts and entrepreneurs in the satellite navigation and application sector attended the conference.Focusing on the theme of"Opening-up,Connectivity and WinWin",officials and well-known experts of satellite navi-  相似文献   
28.
The sapphire (Al2O3) single crystal is a kind of excellent infrared transmission window materials. A large-sized sapphire (Φ225 mm×205 mm, 27.5 kg) was grown by SAPMAC method (sapphire growth technique with micro-pulling and shoulder-expanding at cooled center). Several kinds of inclusion in the large sapphire crystal were investigated by means of an optical microscopy (OM), scan-ning electron microscopy (SEM) and electron probe microanalysis (EPMA). The experimental results show that most inclusions are consisted of solid metallic and non-metallic particles as well as gas pores caused by the impurity of alumina as the raw material, the thermal dissociation of aluminum oxide melt and the reaction of the melt to the crucible material (Mo) at high temperatures. It is also found that in different crystal regions the inclusions are of varied sizes, morphology and chemical compositions. Finally, the measures to reduce and eliminate the inclusions are proposed to improve the crystal quality.  相似文献   
29.
本文研究光纤旋转测量计的补偿电路,分析了电化学线路带来的相位调制的特定性失真。给出了这类失真引起的转角速度测量误差的计算结果。  相似文献   
30.
For rough machining of a complex narrow cavity, e.g., a complex blisk channel on an aero-engine, the typically used cutting tools are the slender cylindrical cutter and conical cutter.Nevertheless, as neither of the two is particularly suited for rough machining, wherein the main purpose is to remove a large volume as quickly as possible, the machining efficiency is low, especially when the part materials are of hard-to-cut types(e.g., Titanium-alloy) for which it often takes days to rough machi...  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