全文获取类型
收费全文 | 3741篇 |
免费 | 7篇 |
国内免费 | 5篇 |
专业分类
航空 | 1549篇 |
航天技术 | 1038篇 |
综合类 | 19篇 |
航天 | 1147篇 |
出版年
2022年 | 15篇 |
2021年 | 37篇 |
2019年 | 16篇 |
2018年 | 224篇 |
2017年 | 172篇 |
2016年 | 129篇 |
2015年 | 50篇 |
2014年 | 112篇 |
2013年 | 136篇 |
2012年 | 132篇 |
2011年 | 218篇 |
2010年 | 192篇 |
2009年 | 250篇 |
2008年 | 237篇 |
2007年 | 189篇 |
2006年 | 74篇 |
2005年 | 124篇 |
2004年 | 98篇 |
2003年 | 106篇 |
2002年 | 83篇 |
2001年 | 117篇 |
2000年 | 36篇 |
1999年 | 53篇 |
1998年 | 61篇 |
1997年 | 43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 | 56篇 |
1983年 | 48篇 |
1982年 | 42篇 |
1981年 | 82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3753条查询结果,搜索用时 421 毫秒
821.
N G Dachev TsPMatviichuk YuN Bankov J V Semkova R T Koleva B T Ivanov YaJTomov V M Petrov V A Shurshakov V V Bengin V S Machmutov N A Panova T A Kostereva V V Temny R Ponomarev YuNTykva 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1992,12(2-3):321-324
Using data from dosimetry-radiometry system "Liulin" on board of "Mir"-space station the particle flux and doserate during September-October, 1989 has been studied. The orbit of the station was 379 km perigee, 410 km apogee and 51.6 degrees inclination. Special attention has been paid to the flux and doserate changes inside the station after intensive solar proton events (SPE) on 29 of September, 1989. The comparison between the doses before and after the solar flares shows increase of the calculated mean dose per day by factor of 10 to 200. During the SPE on the 29 of September the additional dose was 310 mrad. The results of the experiment are compared with the data for the solar proton fluxes obtained on the GOES-7 satellite. 相似文献
822.
A M Alpatov V V Antipov M G Tairbekov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1992,12(1):27-32
In order to reveal the biological significance of gravity, microgravity effects have been studied at the cellular, organism and population levels. The following questions arise. Do any gravity-dependent processes exist in a cell? Is cell adaptation to weightlessness possible; if so, what role may cytoskeleton, the genetic apparatus play in it? What are the consequences of the lack of convection in weightlessness for the performance of morphogenesis? Do the integral characteristics of living beings change in weightlessness? Is there any change in "biological capacity" of space, its resistance to expansion of life? What are the direction and intensity of microgravity action as a factor of natural selection, the driving force of evolution? These problems are discussed from a theoretical point of view, and in the light of results obtained in experiments from aboard biosatellites "Cosmos". 相似文献
823.
The paper is devoted to studies and a quantitative estimation of the influence of scattering of direct solar radiation by particles of tropospheric aerosols in the period of light twilight, close to sunrise and sunset. Polarization measurements of the twilight sky in two broad spectral bands lying near the standard bands V and R form the basis of these studies. The measurements were carried out in 2002 and 2003 at the Southern Laboratory (Crimea) of the Sternberg Astronomical Institute. The twilight period during which the single aerosol scattering becomes significant is isolated. The character of its influence on the intensity and polarization of the twilight sky is demonstrated. A method is suggested to evaluate polarization of the single aerosol scattering and its contribution to the general brightness of the twilight sky background. The method is based on differential characteristics of the background near the zenith and on their correlations with each other. 相似文献
824.
825.
We discuss the use of multilayered annular-plate dampers as rotor supports in turbopumps of the RD-0120 and RD-0146 rocket engines. We present a technique of calculating the elastic and damping characteristics of multilayer corrugated annular supports in the case of the conical precession of the rotor. 相似文献
826.
V. T. Grumondz E. I. Karpezhnikov M. A. Polishchuk M. V. Polishchuk 《Russian Aeronautics (Iz VUZ)》2017,60(4):534-541
The algorithms of controlled descent for unmanned winged gliders are designed taking into account the requirements to the flight trajectory. The calculation results are represented to show the efficiency of the algorithms. 相似文献
827.
Features of fuel atomization and propagation in the flow behind a gas-dynamic stabilizer are considered. Estimations of the influence of transverse jets impulse magnitude on characteristics of mixing behind the stabilizer are obtained by numerical and experimental methods. 相似文献
828.
R.A. Gowen A. Smith A.D. Fortes S. Barber P. Brown P. Church G. Collinson A.J. Coates G. Collins I.A. Crawford V. Dehant J. Chela-Flores A.D. Griffiths P.M. Grindrod L.I. Gurvits A. Hagermann H. Hussmann R. Jaumann A.P. Jones K.H. Joy O. Karatekin K. Miljkovic E. Palomba W.T. Pike O. Prieto-Ballesteros F. Raulin M.A. Sephton S. Sheridan M. Sims M.C. Storrie-Lombardi R. Ambrosi J. Fielding G. Fraser Y. Gao G.H. Jones G. Kargl W.J. Karl A. Macagnano A. Mukherjee J.P. Muller A. Phipps D. Pullan L. Richter F. Sohl J. Snape J. Sykes N. Wells 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
829.
An approach to the analysis of electric arc process stability in plasma systems of ignition is considered depending on the
ignition system power circuit parameters, speed of plasma-generating air, and combustion chamber inlet pressure. Also solved
is the problem on determination of the calculated value of the maximum admissible speed of plasma-generating air that corresponds
to the critical regime of stable arcing in plasma spark plug at the GTE start. 相似文献
830.
A technique of evaluating the micromechanical characteristics (namely, microhardness, microdurability, microbrittleness and
static crack resistance coefficient) using microindentation as applied to plasma zirconia-based thermal barrier coatings is
presented. 相似文献