全文获取类型
收费全文 | 4292篇 |
免费 | 23篇 |
国内免费 | 13篇 |
专业分类
航空 | 2178篇 |
航天技术 | 1158篇 |
综合类 | 4篇 |
航天 | 988篇 |
出版年
2021年 | 26篇 |
2019年 | 23篇 |
2018年 | 194篇 |
2017年 | 163篇 |
2016年 | 80篇 |
2015年 | 46篇 |
2014年 | 74篇 |
2013年 | 95篇 |
2012年 | 118篇 |
2011年 | 240篇 |
2010年 | 196篇 |
2009年 | 256篇 |
2008年 | 230篇 |
2007年 | 223篇 |
2006年 | 73篇 |
2005年 | 142篇 |
2004年 | 104篇 |
2003年 | 101篇 |
2002年 | 76篇 |
2001年 | 129篇 |
2000年 | 71篇 |
1999年 | 70篇 |
1998年 | 87篇 |
1997年 | 58篇 |
1996年 | 94篇 |
1995年 | 114篇 |
1994年 | 115篇 |
1993年 | 58篇 |
1992年 | 73篇 |
1991年 | 36篇 |
1990年 | 34篇 |
1989年 | 78篇 |
1988年 | 29篇 |
1987年 | 24篇 |
1986年 | 33篇 |
1985年 | 95篇 |
1984年 | 90篇 |
1983年 | 65篇 |
1982年 | 68篇 |
1981年 | 99篇 |
1980年 | 19篇 |
1979年 | 25篇 |
1978年 | 29篇 |
1977年 | 28篇 |
1975年 | 29篇 |
1974年 | 23篇 |
1973年 | 21篇 |
1972年 | 20篇 |
1969年 | 20篇 |
1967年 | 20篇 |
排序方式: 共有4328条查询结果,搜索用时 187 毫秒
991.
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
992.
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
993.
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
994.
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
995.
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
996.
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
997.
The results of studying the characteristics of a two-phase flow being formed during adiabatic water efflux through axisymmetric
cylindrical and Laval nozzle channels are presented. Experiments were carried out with saturated water in the range of initial
pressures 0.6–4.0 MPa. The fluid efflux was performed into the air with atmospheric pressure. The generalizing relations for
calculating thrust pulse and critical flowrate were obtained. 相似文献
998.
A. L. Tukmakov V. G. Tonkonog A. G. Kochenkov S. A. Kusyumov 《Russian Aeronautics (Iz VUZ)》2011,54(4):402-411
A physical and mathematical model of a boiling-up fluid flow in the variable crosssection channels is proposed. The numerical
model is based on the solution of the Navier-Stokes nonstationary equations for compressible fluid by the implicit finite-difference
method. We present the results of the numerical modeling for two-phase flow characteristics at the initial stage of the evaporation
process and the steady-state quasistationary flow of a two-phase medium. 相似文献
999.
1000.
V. A. Ivanov D. V. Ivanov N. V. Ryabova Luong Viet Loc E. V. Katkov 《Russian Aeronautics (Iz VUZ)》2017,60(2):286-291
The paper presents the methods and algorithms for positioning the dynamic (moving) objects using the oblique-incidence ionospheric sounding by chirp signals. Full-scale experiments have been performed to determine a distance to an object and its location. 相似文献