全文获取类型
收费全文 | 6121篇 |
免费 | 27篇 |
国内免费 | 18篇 |
专业分类
航空 | 2791篇 |
航天技术 | 1888篇 |
综合类 | 22篇 |
航天 | 1465篇 |
出版年
2021年 | 54篇 |
2019年 | 34篇 |
2018年 | 219篇 |
2017年 | 167篇 |
2016年 | 150篇 |
2015年 | 62篇 |
2014年 | 154篇 |
2013年 | 188篇 |
2012年 | 191篇 |
2011年 | 287篇 |
2010年 | 239篇 |
2009年 | 336篇 |
2008年 | 330篇 |
2007年 | 257篇 |
2006年 | 129篇 |
2005年 | 184篇 |
2004年 | 158篇 |
2003年 | 185篇 |
2002年 | 135篇 |
2001年 | 201篇 |
2000年 | 90篇 |
1999年 | 114篇 |
1998年 | 133篇 |
1997年 | 92篇 |
1996年 | 122篇 |
1995年 | 172篇 |
1994年 | 155篇 |
1993年 | 74篇 |
1992年 | 108篇 |
1991年 | 42篇 |
1990年 | 47篇 |
1989年 | 107篇 |
1988年 | 37篇 |
1987年 | 37篇 |
1986年 | 42篇 |
1985年 | 137篇 |
1984年 | 135篇 |
1983年 | 104篇 |
1982年 | 98篇 |
1981年 | 162篇 |
1980年 | 42篇 |
1979年 | 38篇 |
1978年 | 41篇 |
1977年 | 36篇 |
1976年 | 27篇 |
1975年 | 42篇 |
1974年 | 33篇 |
1973年 | 26篇 |
1972年 | 31篇 |
1971年 | 27篇 |
排序方式: 共有6166条查询结果,搜索用时 967 毫秒
841.
Hardware-in-the-loop testing technology for automatic control, condition monitoring and diagnostics systems of gas turbine engines is described. The technology proposed makes it possible to simulate combinations and chains of unexpected and gradual failures of engines, transducers and actuators. 相似文献
842.
V. A. Olaev 《Russian Aeronautics (Iz VUZ)》2009,52(2):214-220
The algorithmic support of a small-sized navigation system on the basis of the magnetoinertial course transmitter is considered; the support makes it possible to significantly reduce accumulating errors that are due to incomplete data on wind parameters and decrease requirements for random errors of initial data sensors. 相似文献
843.
I. Sh. Sharafeev 《Russian Aeronautics (Iz VUZ)》2009,52(2):255-258
A set of systems for labor standard computer-aided design is described, namely, initial developments, advance and state-of-the art. 相似文献
844.
Yu. G. Kutsenko 《Russian Aeronautics (Iz VUZ)》2009,52(2):208-213
A modification of the Zimont turbulent combustion model is presented; the modification makes it possible to describe processes in diffusion and homogeneous flame fronts as well as to take into account the influence of different factors that cause flame destabilization. The model is based on the equation for a reaction completeness extent (completeness of combustion). The model realization to simulate the premixed combustion is described and the modification of the turbulent combustion model is applied to simulate a process of flameout downstream of the flameholder. 相似文献
845.
Some experimental data on the process of impulsive ultrasonic machining are presented. Also given are the data on variations in the impulsive vibration frequency of a workpiece and a tool. 相似文献
846.
T Takakura E Goto M Tanaka 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,18(4-5):255-258
An axis clinostat was constructed to create micro and negative gravity also a rotated flat disk was constructed with different rotation rates to give increased gravity, by centrifugal force up to 48 g. Rice seeds were grown on agar in tubes at the constant air temperature of 20 degrees C under an average light condition of 110 micromol/m2/sec(PPF). Humidity was not controlled but was maintained above 90%. Since the tube containers were not large enough for long cultivation, shoot and root growth were observed every 12 hours until the sixth day from seeding. The lengths of shoots and roots for each individual plant were measured on the last day. The stem lengths were increased by microgravity but the root lengths were not. Under the negative gravity, negative orthogeotropism and under microgravity, diageotropism was observed. No significant effect of increased gravity was observed on shoot and root growth. 相似文献
847.
848.
849.
V. A. Ryabyi V. A. Obukhov A. P. Kirpichnikov P. E. Masherov A. I. Mogulkin 《Russian Aeronautics (Iz VUZ)》2015,58(4):448-453
A technique of integral diagnostics for an RF inductively coupled plasma gas discharge unit of an ion thruster is proposed. This technique includes a priori measurements of antenna coil electrical parameters in free space and in assembled state as well as experimental determination of the antenna coil currents with and without discharge. 相似文献
850.
G. A. Gusev B. N. Lomonosov K. M. Pichkhadze N. G. Polukhina V. A. Ryabov T. Saito V. K. Sysoev E. L. Feinberg V. A. Tsarev V. A. Chechin 《Cosmic Research》2006,44(1):19-38
An estimate of the feasibility of the ultrahigh-energy cosmic ray and neutrino detection using a lunar satellite-borne radio receiver is presented. The data obtained in the proposed experiment will make resolving the current contradictions in the ultrahigh-energy cosmic ray spectra measured with the major ground-based instruments possible. Moreover, they will enable us to considerably extend the accessible energy range and to check predictions of various models of the origin of the highest-energy particles in the Universe. At the same time the lunar radio detector provides a means of searching for ultrahigh-energy neutrinos with a high sensitivity combined with a very large target effective mass. 相似文献