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   152篇
  免费   18篇
  国内免费   26篇
航空   81篇
航天技术   16篇
综合类   10篇
航天   89篇
  2024年   8篇
  2023年   9篇
  2022年   15篇
  2021年   3篇
  2020年   6篇
  2019年   8篇
  2018年   8篇
  2017年   4篇
  2016年   6篇
  2015年   2篇
  2014年   7篇
  2013年   2篇
  2012年   7篇
  2011年   1篇
  2010年   5篇
  2009年   4篇
  2008年   6篇
  2007年   8篇
  2006年   14篇
  2005年   10篇
  2004年   5篇
  2003年   3篇
  2002年   4篇
  2001年   7篇
  2000年   2篇
  1999年   1篇
  1998年   8篇
  1997年   3篇
  1996年   2篇
  1995年   4篇
  1994年   7篇
  1993年   3篇
  1992年   3篇
  1991年   3篇
  1989年   3篇
  1988年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1975年   1篇
排序方式: 共有196条查询结果,搜索用时 15 毫秒
121.
In vitro edible muscle protein production system (MPPS): stage 1, fish   总被引:1,自引:0,他引:1  
The working efficiency and state-of-mind of a Space vehicle crew on long-term missions is dependent on the suitability of living conditions including food. Our purpose was to establish the feasibility of an in vitro muscle protein production system (MPPS) for the fabrication of surrogate muscle protein constructs as food products for Space travelers. In the experimental treatments, we cultivated the adult dorsal abdominal skeletal muscle mass of Carassius (Gold fish). An ATCC fish fibroblast cell line was used for tissue engineering investigations. No antibiotics were used during any phase of the research. Our four treatments produced these results: a low contamination rate, self-healing, cell proliferation, a tissue engineered construct of non-homologous co-cultured cells with explants, an increase in tissue size in homologous co-cultures of explants with crude cell mixtures, maintenance of explants in media containing fetal bovine serum substitutes, and harvested explants which resembled fresh fish filets.

We feel that not only have we pointed the way to an innovative, viable means of supplying safe, healthy, nutritious food to Space voyagers on long journeys, but our research also points the way to means of alleviating food supply and safety problems in both the public and private sectors worldwide.  相似文献   

122.
123.
用介电常数监测酯类润滑油   总被引:2,自引:0,他引:2  
  相似文献   
124.
光机扫描仪通过光机扫描和平台运动获取图像。虽然推扫式成像仪应用越来越普遍,但光机扫描仪在很多领域一直广泛应用。文章对光机扫描仪的像质评价和优化设计问题进行了探讨。首先对光机扫描仪空间分辨率和辐射分辨率的评价方法和需求优化进行了探讨,然后以中巴地球资源卫星(CBERS)红外多光谱扫描仪(IRMSS)为例,介绍了通过对GSD、MTF和SNR进行折中考虑来对光机扫描仪进行优化设计的思路。  相似文献   
125.
文章就采样成像系统的CTF和MTF的关系进行了探讨。  相似文献   
126.
文章介绍了CBERS -1卫星红外多光谱扫描仪(IRMSS)的设计与在轨运行情况  相似文献   
127.
Because of long duration travel outside the Earth's magnetic field, the effect of iron-rich high charge and energy (HZE) particles in Galactic Cosmic Rays on human body is the major concern in radiation protection. Recently attention has been directed to effects on the central nervous system in addition to mutagenic effects. In particular, a reduction in striatal dopamine content on nigrostriatal dopaminergic system has been reported by investigators using accelerated iron ions in ground-based mammalian studies. In addition, studies of the pathophysiology of Parkinson's disease demonstrated that excess iron cause a reduction in the dopamine content in the substantia nigra. This suggests an intriguing possibility to explain the selective detrimental effects of HZE particles on the dopaminergic system. Should these particles have biochemical effects, possible options for countermeasures are: (1) nutritional prevention, (2) medication, and (3) surgical placement of a stimulator electrode at a specific anatomic site in the basal ganglia.  相似文献   
128.
Owing to the unique advantages in flight altitude, dwelling time and wide coverage area,stratospheric airships provide permanent monitoring and surveillance for both civil and military applications. Here we propose a semi-rigid stratosphere airship design with circumferential highpressure inflatable rings and a longitudinal carbon fiber skeleton supported inside. We perform numerical simulations to analyze the deformation characteristics during the whole ascending and descending process. An equi...  相似文献   
129.
The presence of sulfur mass-independent fractionation (S-MIF) in sediments more than 2.45?×?10(9) years old is thought to be evidence for an early anoxic atmosphere. Photolysis of sulfur dioxide (SO(2)) by UV light with λ?相似文献   
130.
In October of 2005, the European Space Agency (ESA) and Alcatel Alenia Spazio released a "call to academia for innovative concepts and technologies for lunar exploration." In recent years, interest in lunar exploration has increased in numerous space programs around the globe, and the purpose of our study, in response to the ESA call, was to draw on the expertise of researchers and university students to examine science questions and technologies that could support human astrobiology activity on the Moon. In this mini review, we discuss astrobiology science questions of importance for a human presence on the surface of the Moon and we provide a summary of key instrumentation requirements to support a lunar astrobiology laboratory.  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