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   3711篇
  免费   7篇
  国内免费   5篇
航空   1510篇
航天技术   1044篇
综合类   19篇
航天   1150篇
  2022年   15篇
  2021年   37篇
  2019年   17篇
  2018年   205篇
  2017年   163篇
  2016年   129篇
  2015年   48篇
  2014年   112篇
  2013年   134篇
  2012年   132篇
  2011年   218篇
  2010年   190篇
  2009年   251篇
  2008年   237篇
  2007年   188篇
  2006年   75篇
  2005年   124篇
  2004年   99篇
  2003年   106篇
  2002年   84篇
  2001年   115篇
  2000年   36篇
  1999年   53篇
  1998年   61篇
  1997年   42篇
  1996年   43篇
  1995年   80篇
  1994年   61篇
  1993年   38篇
  1992年   47篇
  1991年   10篇
  1990年   19篇
  1989年   41篇
  1988年   11篇
  1987年   17篇
  1986年   16篇
  1985年   70篇
  1984年   57篇
  1983年   48篇
  1982年   42篇
  1981年   84篇
  1980年   25篇
  1979年   16篇
  1978年   14篇
  1977年   17篇
  1976年   13篇
  1975年   13篇
  1974年   11篇
  1972年   13篇
  1971年   11篇
排序方式: 共有3723条查询结果,搜索用时 15 毫秒
181.
We consider the peculiarities of application for the cabin indicating systems of secondary information display, formulate and systematize the compositional and technical requirements for display systems and their elements. The tendencies and lines in the development of head-up displays for avionics and autobasing complexes were determined. The technique of calculating optics of such display systems with the use of electronic distortion compensation is presented.  相似文献   
182.
The paper describes a device and a technique of forming the information processing algorithms used in the integrated acoustic monitoring system for jet fuel tanks, intended for monitoring the level, density and mass of liquid products.  相似文献   
183.
The results of investigating free oscillations of the International Space Station construction appearing during spacecraft docking and undocking are described. The study is carried out using the measurement data of the low-frequency MAMS accelerometer. Several intervals of measurements performed in 2005 and 2006 were chosen to be studied. For chosen intervals, only the data intervals corresponding to the process of free attenuation of the oscillations construction elements were analyzed. Characteristic frequencies of elastic oscillations of the station construction and attenuation coefficients corresponding to them are found. The comparative analysis of the results obtained for various docking ports (nodes) is carried out. The described study is performed as a part of the technical experiment “The ISS Environment” carried out onboard the station in accordance with the Russian program of scientific and engineering experiments.  相似文献   
184.
The paper adduces the relators for algebraic operations on graphs using the numeric codes of the graphs. The special algebra of codes has been devised with consideration of the principles of graph transformation. This paper demonstrates the relevance of numeric coding of graphs for solving the problems of enumeration, systematization, and compact representation of the information about the structural and functional characteristics of the systems of flow distribution and conversion of rocket and space technology and for conducting the modeling transformations of given systems in the course of the structural and functional studies as well.  相似文献   
185.
Numerous discoveries of asteroids unknown earlier led to a multiple increase in the number of information on small bodies of the Solar System. Huge volumes of information accumulated and obtained at observations of objects approaching the Earth’s orbit require storing and prompt processing, presenting more and more possibilities for studying distributions of small bodies of the Solar System and ways of their evolution. That is why development of information systems which will contain large volumes of data on small bodies of the Solar System and facilities for processing these data is actual and promising direction of activity.  相似文献   
186.
A concept of monitoring for material properties with residual life estimation of rotor blades for gas turbine engines is proposed. The structure of on-board control and conditionmonitoring system based on the intelligent pyrometer module with the algorithm for calculating the residual life of turbine rotor blades is described.  相似文献   
187.
This paper presents a composite model of a flight simulator. This simulator is intended for carrying out investigative tests of flight dynamics imitation models of a hingeless rotor helicopter. A schematic diagram, composition and operation channels of the flight simulator software are presented. A possibility of applying the control lag is estimated.  相似文献   
188.
Methods to control flow have been considered in order to reduce end losses in blade rows of GTE gas turbines by means of measures taken at the design stage.  相似文献   
189.
190.
Spite  F.  Spite  M.  Hill  V. 《Space Science Reviews》1998,84(1-2):155-160
The relation between the lithium abundance observed in Population II stars and the primordial abundance, is still an open question (see Cayrel and Duncan, this meeting). A few recent results are discussed. HIPPARCOS data show that the standard model of stellar evolution can explain the 6Li detection in HD 84937, suggesting a negligible depletion of 7Li. A slope in the Li/Teff relation for Pop II dwarfs and a spread of their Li abundance have been advocated, and both used as arguments in favor of Li depletion. The slope is not confirmed when two other independent temperature scales are used. The Li scatter around the plateau is hardly larger than the scatter predicted from determination errors. Hints from a scatter of Li in subgiants of the globular cluster M92 are not completely conclusive. The determination of more accurate Li abundances in the Pop II stars is an urgent but difficult task, requiring better model atmosphere (better convection treatment) and the help of observational data about Pop II stars (such as long base interferometry).  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