全文获取类型
收费全文 | 5267篇 |
免费 | 668篇 |
国内免费 | 500篇 |
专业分类
航空 | 2805篇 |
航天技术 | 1473篇 |
综合类 | 435篇 |
航天 | 1722篇 |
出版年
2024年 | 17篇 |
2023年 | 52篇 |
2022年 | 114篇 |
2021年 | 174篇 |
2020年 | 134篇 |
2019年 | 115篇 |
2018年 | 244篇 |
2017年 | 213篇 |
2016年 | 174篇 |
2015年 | 174篇 |
2014年 | 249篇 |
2013年 | 236篇 |
2012年 | 252篇 |
2011年 | 320篇 |
2010年 | 334篇 |
2009年 | 374篇 |
2008年 | 331篇 |
2007年 | 264篇 |
2006年 | 195篇 |
2005年 | 205篇 |
2004年 | 149篇 |
2003年 | 182篇 |
2002年 | 196篇 |
2001年 | 190篇 |
2000年 | 137篇 |
1999年 | 140篇 |
1998年 | 109篇 |
1997年 | 111篇 |
1996年 | 112篇 |
1995年 | 108篇 |
1994年 | 86篇 |
1993年 | 59篇 |
1992年 | 75篇 |
1991年 | 43篇 |
1990年 | 38篇 |
1989年 | 51篇 |
1988年 | 31篇 |
1987年 | 26篇 |
1986年 | 30篇 |
1985年 | 78篇 |
1984年 | 42篇 |
1983年 | 27篇 |
1982年 | 40篇 |
1981年 | 76篇 |
1980年 | 18篇 |
1978年 | 10篇 |
1977年 | 14篇 |
1976年 | 11篇 |
1975年 | 14篇 |
1974年 | 17篇 |
排序方式: 共有6435条查询结果,搜索用时 0 毫秒
591.
S. O. Karpenko N. V. Kupriyanova M. Yu. Ovchinnikov V. I. Penkov A. S. Selivanov O. E. Khromov 《Cosmic Research》2010,48(6):517-525
The results of designing the attitude control system of the first Russian nanosatellite TNS-0 no. 1 providing orientation of its longitudinal axis along the local geomagnetic field induction vector are presented. The system
consists of a permanent magnet and two sets of hysteresis rods. The magnetic and geometric parameters of the magnet and rods
are calculated. The influence of the permanent magnet field on the hysteresis rods and mutual influence of the rods in the
case of compact satellite packaging are analyzed. Examples of calculations of transient processes and steady-state angular
satellite motion are presented. 相似文献
592.
593.
Dynamics of planets around other stars that demonstrate a variety of possible characteristics is of interest from the point
of view of realization of new scenarios of evolution which have not been realized in the Solar System. We consider the rotational
evolution of exoplanets under the action of gravitational perturbations and magnetic disturbances using the methods of quality
analysis and theory of bifurcation of multiparametric differential equations that describe evolution of non-resonant rotation
of a dynamically symmetric planet magnetized along its symmetry axis. We analyze 64 phase portraits describing the evolution
of angular momentum vector L for all possible values of planet parameters. The values of parameters are determined for the case when the direct rotation
of a planet is changed for its retrograde rotation. 相似文献
594.
目的介绍一种在Labwindows/CVI环境下调用Word的实现方法;方法结合具体的实例,实现对Word文档的调用;结果该方法可以按照规定的格式自动生成Word文档;结论提高了软件的效率和自动化程度。 相似文献
595.
Nikolai M. Gavrilov Andrej V. Koval Alexander I. Pogoreltsev Elena N. Savenkova 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Parameterization of dynamical and thermal effects of stationary orographic gravity waves (OGWs) generated by the Earth’s surface topography is incorporated into a numerical model of general circulation of the middle and upper atmosphere. Responses of atmospheric general circulation and characteristics of planetary waves at altitudes from the troposphere up to the thermosphere to the effects of OGWs propagating from the earth surface are studied. Changes in atmospheric circulation and amplitudes of planetary waves due to variations of OGW generation and propagation in different seasons are considered. It is shown that during solstices the main OGW dynamical and heat effects occur in the middle atmosphere of winter hemispheres, where changes in planetary wave amplitudes due to OGWs may reach up to 50%. During equinoxes OGW effects are distributed more homogeneously between northern and southern hemispheres. 相似文献
596.
A comparison of temporal profiles of low-energy ion intensity and magnetic field magnitude in different periods of solar activity
in the outer heliosphere is carried out using the data of the Voyager 1 and Voyager 2 spacecraft. It is shown that temporal, spectral, and statistical characteristics of particle fluxes and magnetic field in
the heliospheric regions before and after the terminal shock in 2002–2008 had similar dynamics in different hemispheres. This
similarity allowed one to assume that, in the region of the inner heliospheric boundary, a quasistable spatial structure existed
moving together with the terminal shock in accordance with the solar wind pressure, as well as, probably, under the action
of the interstellar medium. It was revealed that the spatial dimensions of most details of this structure are less on Voyager 2, which, probably, is due to variation of the solar activity level, difference in latitude of spacecraft disposition, and
also the influence of the interstellar magnetic field. 相似文献
597.
598.
I. Antonenko G.R. Osinski M. Battler M. Beauchamp L. Cupelli A. Chanou R. Francis M.M. Mader C. Marion E. McCullough A.E. Pickersgill L.J. Preston B. Shankar T. Unrau D. Veillette 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Remote robotic data provides different information than that obtained from immersion in the field. This significantly affects the geological situational awareness experienced by members of a mission control science team. In order to optimize science return from planetary robotic missions, these limitations must be understood and their effects mitigated to fully leverage the field experience of scientists at mission control. 相似文献
599.
In this paper, we consider some typical values of motion parameters in exceptional situations when approaching to the helicopter critical flight regimes and present a technique for constructing the partial and integral informative functions of hazards at current flight regimes. Also described are the possibilities of their use for solving the problems of warning, informative crew support, and synthesizing the control algorithms to remove helicopter from the exceptional situation occurred. 相似文献
600.
A. Yu. Liss 《Russian Aeronautics (Iz VUZ)》2012,55(2):136-143
We present the materials, which substantiate the application of a rather simple approximate method of accounting for disturbances of the airflow around the helicopter main rotor blades; in this case, the disturbances are caused by vortices that come down from the blade ends. It is shown that these disturbances influence significantly the varying blade loads. 相似文献