全文获取类型
收费全文 | 2552篇 |
免费 | 4篇 |
国内免费 | 11篇 |
专业分类
航空 | 978篇 |
航天技术 | 882篇 |
综合类 | 9篇 |
航天 | 698篇 |
出版年
2021年 | 26篇 |
2019年 | 10篇 |
2018年 | 134篇 |
2017年 | 92篇 |
2016年 | 61篇 |
2015年 | 23篇 |
2014年 | 78篇 |
2013年 | 86篇 |
2012年 | 73篇 |
2011年 | 129篇 |
2010年 | 93篇 |
2009年 | 140篇 |
2008年 | 165篇 |
2007年 | 92篇 |
2006年 | 58篇 |
2005年 | 78篇 |
2004年 | 79篇 |
2003年 | 88篇 |
2002年 | 58篇 |
2001年 | 101篇 |
2000年 | 39篇 |
1999年 | 42篇 |
1998年 | 52篇 |
1997年 | 35篇 |
1996年 | 52篇 |
1995年 | 51篇 |
1994年 | 36篇 |
1993年 | 24篇 |
1992年 | 41篇 |
1991年 | 11篇 |
1990年 | 15篇 |
1989年 | 40篇 |
1988年 | 16篇 |
1987年 | 23篇 |
1986年 | 22篇 |
1985年 | 72篇 |
1984年 | 43篇 |
1983年 | 34篇 |
1982年 | 43篇 |
1981年 | 76篇 |
1980年 | 18篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 13篇 |
1976年 | 9篇 |
1975年 | 14篇 |
1974年 | 15篇 |
1973年 | 9篇 |
1971年 | 7篇 |
1970年 | 6篇 |
排序方式: 共有2567条查询结果,搜索用时 15 毫秒
91.
K. S. Kuz’mina I. K. Marchevskii V. S. Moreva E. P. Ryatina 《Russian Aeronautics (Iz VUZ)》2017,60(3):398-405
A high-accuracy numerical scheme is proposed for vortex methods of flow simulation around airfoils of arbitrary shape including airfoils with sharp edges, because it does not require the solution continuity on the airfoil. 相似文献
92.
The paper provides a method for multi-criteria selection of the optimal structural layout option based on a fuzzy logic inference that allows for uncertainties in engineering and operates with heterogeneous information of the qualitative and quantitative nature for the systems being designed. 相似文献
93.
94.
95.
Very Long Baseline Interferometry (VLBI) is a differential technique observing radiation of compact extra-galactic radio sources with pairs of radio telescopes. For these observations, the frequency standards at the telescopes need to have very high stability. In this article we discuss why this is, and we investigate exactly how precise the frequency standards need to be. Four areas where good clock performance is needed are considered: coherence, geodetic parameter estimation, correlator synchronization, and UT1 determination. We show that in order to ensure the highest accuracy of VLBI, stability similar to that of a hydrogen maser is needed for time-scales up to a few hours. In the article, we are considering both traditional VLBI where extra-galactic radio sources are observed, as well as observation of man-made artificial radio sources emitted by satellites or spacecrafts. 相似文献
96.
P. V. Bulat M. P. Bulat I. A. Volobuev A. A. Levikhin 《Russian Aeronautics (Iz VUZ)》2018,61(3):420-424
The bearing capacity of hybrid segmented bearings with different groove systems is compared. The research establishes that the system with a crescent groove has the best characteristics. 相似文献
97.
98.
99.
Based on an integrated approach, we solve the optimization problem for energy content and weight-dimensional characteristics of the electric servo drive by synthesis of structure and analysis of characteristics for different power supplies. The generalized power supply model, developed for different power supply of drive control systems, is given. 相似文献
100.
We consider the stability of stationary motions of a model of a spacecraft as a system of coaxial bodies with small asymmetry caused by the shift of the axes of dynamic symmetry of bodies relative to the axis of rotation. We determine the stationary motions of the system; their stability is studied with respect to both the projections of angular velocity and the position of the axis of rotation. The sufficient conditions for the stability of these stationary motions are obtained by constructing a Lyapunov function, and the necessary conditions are obtained by analyzing the corresponding linearized equations of perturbed motion. 相似文献