全文获取类型
收费全文 | 4009篇 |
免费 | 4篇 |
国内免费 | 21篇 |
专业分类
航空 | 2083篇 |
航天技术 | 1108篇 |
综合类 | 10篇 |
航天 | 833篇 |
出版年
2019年 | 19篇 |
2018年 | 194篇 |
2017年 | 157篇 |
2016年 | 53篇 |
2015年 | 36篇 |
2014年 | 56篇 |
2013年 | 78篇 |
2012年 | 104篇 |
2011年 | 244篇 |
2010年 | 200篇 |
2009年 | 249篇 |
2008年 | 268篇 |
2007年 | 213篇 |
2006年 | 76篇 |
2005年 | 135篇 |
2004年 | 102篇 |
2003年 | 90篇 |
2002年 | 57篇 |
2001年 | 84篇 |
2000年 | 50篇 |
1999年 | 66篇 |
1998年 | 82篇 |
1997年 | 52篇 |
1996年 | 63篇 |
1995年 | 79篇 |
1994年 | 77篇 |
1993年 | 53篇 |
1992年 | 64篇 |
1991年 | 34篇 |
1990年 | 30篇 |
1989年 | 72篇 |
1988年 | 29篇 |
1987年 | 31篇 |
1986年 | 35篇 |
1985年 | 124篇 |
1984年 | 68篇 |
1983年 | 59篇 |
1982年 | 58篇 |
1981年 | 105篇 |
1980年 | 36篇 |
1979年 | 27篇 |
1978年 | 25篇 |
1977年 | 28篇 |
1976年 | 18篇 |
1975年 | 32篇 |
1974年 | 19篇 |
1973年 | 27篇 |
1972年 | 20篇 |
1970年 | 24篇 |
1969年 | 26篇 |
排序方式: 共有4034条查询结果,搜索用时 15 毫秒
941.
942.
V. A. Sadovnichii V. V. Alexandrov D. I. Bugrov S. S. Lemak V. B. Pakhomov M. I. Panasyuk V. L. Petrov I. V. Yashin 《Space Science Reviews》2018,214(2):51
The IMISS-1 experiment represents the second step in solving the problem of the creation of the gaze stabilization corrector. This device is designed to correct the effect of the gaze stabilization delay under microgravity. IMISS-1 continues research started by the Tat’yana-2 satellite. This research will be continued on board the International Space Station. At this stage we study the possibility of registration of angular and linear accelerations acting on the sensitive mass in terms of Low Earth Orbit flight, using MEMS sensors. 相似文献
943.
This paper studies the dynamic loads of bevel gears with circular and straight teeth with the overlap factors less than two (εα < 2) and more than two (εα > 2). The advantages of the gears with straight teeth with εα > 2 are shown. 相似文献
944.
Avionics (aeronautics and aerospace) industries must rely on components and systems of demonstrated high reliability. For this, handbook-based methods have been traditionally used to design for reliability, develop test plans, and define maintenance requirements and sustainment logistics. However, these methods have been criticized as flawed and leading to inaccurate and misleading results. In its recent report on enhancing defense system reliability, the U.S. National Academy of Sciences has recently discredited these methods, judging the Military Handbook (MIL-HDBK-217) and its progeny as invalid and inaccurate. This paper discusses the issues that arise with the use of handbook-based methods in commercial and military avionics applications. Alternative approaches to reliability design (and its demonstration) are also discussed, including similarity analysis, testing, physics-of-failure, and data analytics for prognostics and systems health management. 相似文献
945.
946.
The equations of the mathematical model are solved in terms of special functions. The results for the design scheme of the aircraft forebody are obtained with a guaranteed accuracy by the stable method of functional normalization. 相似文献
947.
This paper demonstrates that in transition from the one-dimensional longitudinal-channel motion of the coolant in the regenerative cooling system of the liquid propellant engine to the twodimensional (interchannel) channel motion (transpiration) through a porous mesh material (PMM), the hydraulic losses decrease. Experimental data on PMM hydraulic resistance coefficients and heat transfer in porous paths with the interchannel coolant transpiration (ICCT) is presented. 相似文献
948.
We review the present theoretical and numerical understanding of magnetic field amplification in cosmic large-scale structure, on length scales of galaxy clusters and beyond. Structure formation drives compression and turbulence, which amplify tiny magnetic seed fields to the microGauss values that are observed in the intracluster medium. This process is intimately connected to the properties of turbulence and the microphysics of the intra-cluster medium. Additional roles are played by merger induced shocks that sweep through the intra-cluster medium and motions induced by sloshing cool cores. The accurate simulation of magnetic field amplification in clusters still poses a serious challenge for simulations of cosmological structure formation. We review the current literature on cosmological simulations that include magnetic fields and outline theoretical as well as numerical challenges. 相似文献
949.