全文获取类型
收费全文 | 6514篇 |
免费 | 7篇 |
国内免费 | 71篇 |
专业分类
航空 | 3518篇 |
航天技术 | 1939篇 |
综合类 | 24篇 |
航天 | 1111篇 |
出版年
2018年 | 185篇 |
2017年 | 148篇 |
2016年 | 67篇 |
2015年 | 39篇 |
2014年 | 85篇 |
2013年 | 138篇 |
2012年 | 185篇 |
2011年 | 304篇 |
2010年 | 243篇 |
2009年 | 318篇 |
2008年 | 339篇 |
2007年 | 275篇 |
2006年 | 142篇 |
2005年 | 197篇 |
2004年 | 131篇 |
2003年 | 172篇 |
2002年 | 102篇 |
2001年 | 180篇 |
2000年 | 110篇 |
1999年 | 142篇 |
1998年 | 164篇 |
1997年 | 123篇 |
1996年 | 170篇 |
1995年 | 216篇 |
1994年 | 182篇 |
1993年 | 124篇 |
1992年 | 129篇 |
1991年 | 76篇 |
1990年 | 62篇 |
1989年 | 138篇 |
1988年 | 62篇 |
1987年 | 66篇 |
1986年 | 60篇 |
1985年 | 196篇 |
1984年 | 150篇 |
1983年 | 131篇 |
1982年 | 133篇 |
1981年 | 177篇 |
1980年 | 58篇 |
1979年 | 41篇 |
1978年 | 50篇 |
1977年 | 53篇 |
1976年 | 38篇 |
1975年 | 58篇 |
1974年 | 38篇 |
1973年 | 42篇 |
1972年 | 51篇 |
1971年 | 42篇 |
1970年 | 44篇 |
1969年 | 37篇 |
排序方式: 共有6592条查询结果,搜索用时 46 毫秒
281.
N. M. Bodunov 《Russian Aeronautics (Iz VUZ)》2011,54(1):89-94
A mathematical model of the process of bending and rolling the thin-walled components is presented taking into account the
geometrical nonlinearity. Also presented is the technique for calculating the setup variables of bending equipment, which
is based on reduction of the initial differential boundary-value problem to the discrete one with the use of the finite difference
method. 相似文献
282.
283.
I. Martínez J.M. Perales 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The experimental results obtained in experiment “STACO” made on board the Spacelab D-2 are re-visited, with image-analysis tools not then available. The configuration consisted of a liquid bridge between two solid supporting discs. An expected breakage occurred during the experiment. The recorded images are analysed and the measured behaviour compared with the results of a three dimensional model of the liquid dynamics, obtaining a much better fit than with linear models. 相似文献
284.
The paper presents a technique of forming and evaluating the allowable clearance between a launch vehicle fairing and spacecraft. 相似文献
285.
This paper deals with the technical features of designing an information-controlling system to prevent critical operating conditions of the helicopter flight, a technique for evaluating its effectiveness, analysis and synthesis of the measurement channels, forming of warning signals, and information support of the crew in abnormal situations. 相似文献
286.
Paul A. Crowther Joanne L. Bibby James P. Furness J. Simon Clark 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
We highlight how the downward revision in the distance to the star cluster associated with SGR 1806–20 by Bibby et al. (2008) reconciles the apparent low contamination of BATSE short GRBs by intense flares from extragalactic magnetars without recourse to modifying the frequency of one such flare per 30 years per Milky Way galaxy. We also discuss the variety in progenitor initial masses of magnetars based upon cluster ages, ranging from ∼50 M⊙ for SGR 1806–20 and AXP CXOU J164710.2–455216 in Westerlund 1 to ∼17 M⊙ for SGR 1900+14 according to Davies et al. (2009) and presumably also 1E 1841–045 if it originated from one of the massive RSG clusters #2 or #3. 相似文献
287.
We determine the behavior of onboard gas-generator flowrate for generating the cavitation flow around a hybrid aerial underwater vehicle by using an annular wing on the underwater trajectory section. 相似文献
288.
C. J. Hansen M. A. Caplinger A. Ingersoll M. A. Ravine E. Jensen S. Bolton G. Orton 《Space Science Reviews》2017,213(1-4):475-506
Junocam is a wide-angle camera designed to capture the unique polar perspective of Jupiter offered by Juno’s polar orbit. Junocam’s four-color images include the best spatial resolution ever acquired of Jupiter’s cloudtops. Junocam will look for convective clouds and lightning in thunderstorms and derive the heights of the clouds. Junocam will support Juno’s radiometer experiment by identifying any unusual atmospheric conditions such as hotspots. Junocam is on the spacecraft explicitly to reach out to the public and share the excitement of space exploration. The public is an essential part of our virtual team: amateur astronomers will supply ground-based images for use in planning, the public will weigh in on which images to acquire, and the amateur image processing community will help process the data. 相似文献
289.
The paper discusses the applicability of cold gaseous nitrogen as a model working fluid in testing the hydrogen pump seals for power plants by three-dimensional modeling. 相似文献
290.
This paper considers the axisymmetric transverse vibrations of aircraft nonuniform structural elements that are introduced by a thermal shock. Analytical solutions have been obtained and their numerical analysis has been performed. 相似文献