全文获取类型
收费全文 | 2047篇 |
免费 | 312篇 |
国内免费 | 128篇 |
专业分类
航空 | 509篇 |
航天技术 | 1038篇 |
综合类 | 59篇 |
航天 | 881篇 |
出版年
2024年 | 1篇 |
2023年 | 36篇 |
2022年 | 40篇 |
2021年 | 82篇 |
2020年 | 89篇 |
2019年 | 60篇 |
2018年 | 91篇 |
2017年 | 35篇 |
2016年 | 64篇 |
2015年 | 65篇 |
2014年 | 216篇 |
2013年 | 126篇 |
2012年 | 95篇 |
2011年 | 187篇 |
2010年 | 129篇 |
2009年 | 128篇 |
2008年 | 118篇 |
2007年 | 96篇 |
2006年 | 93篇 |
2005年 | 111篇 |
2004年 | 77篇 |
2003年 | 45篇 |
2002年 | 77篇 |
2001年 | 50篇 |
2000年 | 59篇 |
1999年 | 66篇 |
1998年 | 45篇 |
1997年 | 24篇 |
1996年 | 29篇 |
1995年 | 28篇 |
1994年 | 11篇 |
1993年 | 17篇 |
1992年 | 12篇 |
1991年 | 18篇 |
1990年 | 15篇 |
1989年 | 16篇 |
1988年 | 22篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1984年 | 2篇 |
排序方式: 共有2487条查询结果,搜索用时 15 毫秒
81.
In the past two years, space life science research in China is characterized by a wide area of basic researches for providing foundation for the future China Space Station. The effect of microgravity and radiation was further studied from physiology phenomena to the level of bio-molecule mechanisms. Chinese space life science is maturing in a new era of comprehensive development. Here, we review and summarize researches on space life sciences which were contributed by Chinese scientists. 相似文献
82.
To develop an understanding of near-Earth space's response to solar activities and the coupling among different layers in geospace, China has initiated a ground base program to monitor China's geospace environment called the Meridian Space Weather Monitoring Project (Chinese Meridian Project). The effort consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N latitude. Each observatory is equipped with multiple instruments to measure key parameters such as the baseline and time-varying geomagnetic field, as well as the middle and upper atmosphere and ionosphere from about 20 to 1000 kilometers. This project started collecting data in 2012. We will give a brief introduction to the Chinese Meridian Project, and present recent scientific results mainly in ionospheric and atmospheric studies. 相似文献
83.
With the complete success of the 2nd stage of Chinese Manned Space Program (CMSP), several science researches have been performed on Tiangong-1 experimental spacelab, which was docked with three Shenzhou spaceships one after another. The China's real spacelab, Tiangong-2 will be launched in 2015, docked with a Shenzhou spaceship soon. After six months, it will be docked with the first Chinese cargo ship (Tianzhou-1). More space science researches, involving with space biology, fluid physics, fundamental physics, materials science, Earth science, astronomy and space environmental science, will be operated on Tiangong-2 spacelab, and crewed and cargo spaceships. Furthermore, the considerable large-scale space utilization of Shina's Space Station is planned. The research fields include yet not limited to space medicine and physiology, space life science and biotechnology, fluid physics and combustion in microgravity, space material science, and fundamental physics in microgravity, space astronomy, Earth science, space physics and space environment utilization, technology demonstration. 相似文献
84.
85.
86.
87.
88.
89.
介绍国际电(ITU)和空间频率协调组(SFGC)关于月球与深空探测频率使用的一些规定和建议,研究国外月球与深空探测频率使用规划和发展趋势,探讨我国月球与深空探测频率使用需求,提出我国月球与深空探测频率建议和发展方向。 相似文献
90.
分析了航天器深空飞行中与遥控工作密切相关的信息传输时延,分析了遥控工作面对的控制实时性、控制精度、控制验证等方面的问题;从遥控工作的控制方式、发令工作模式、遥控工作机制、发令时间补偿等方面提出了解决思路。 相似文献