全文获取类型
收费全文 | 2526篇 |
免费 | 4篇 |
国内免费 | 6篇 |
专业分类
航空 | 1187篇 |
航天技术 | 913篇 |
综合类 | 9篇 |
航天 | 427篇 |
出版年
2021年 | 18篇 |
2019年 | 16篇 |
2018年 | 58篇 |
2017年 | 35篇 |
2016年 | 39篇 |
2015年 | 12篇 |
2014年 | 55篇 |
2013年 | 89篇 |
2012年 | 55篇 |
2011年 | 85篇 |
2010年 | 71篇 |
2009年 | 118篇 |
2008年 | 139篇 |
2007年 | 58篇 |
2006年 | 63篇 |
2005年 | 64篇 |
2004年 | 64篇 |
2003年 | 85篇 |
2002年 | 43篇 |
2001年 | 92篇 |
2000年 | 48篇 |
1999年 | 65篇 |
1998年 | 69篇 |
1997年 | 66篇 |
1996年 | 64篇 |
1995年 | 87篇 |
1994年 | 86篇 |
1993年 | 41篇 |
1992年 | 50篇 |
1991年 | 15篇 |
1990年 | 24篇 |
1989年 | 51篇 |
1988年 | 32篇 |
1987年 | 20篇 |
1986年 | 28篇 |
1985年 | 73篇 |
1984年 | 70篇 |
1983年 | 42篇 |
1982年 | 69篇 |
1981年 | 67篇 |
1980年 | 17篇 |
1979年 | 10篇 |
1978年 | 31篇 |
1977年 | 12篇 |
1975年 | 24篇 |
1974年 | 16篇 |
1973年 | 16篇 |
1972年 | 16篇 |
1970年 | 9篇 |
1969年 | 12篇 |
排序方式: 共有2536条查询结果,搜索用时 15 毫秒
621.
B. Bidaine R. Warnant 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The ionospheric effect remains one of the main factors limiting the accuracy of Global Navigation Satellite Systems (GNSS) including Galileo. For single frequency users, this contribution to the error budget will be mitigated by an algorithm based on the NeQuick global ionospheric model. This quick-run empirical model provides flexible solutions for combining ionospheric information obtained from various sources, from GNSS to ionosondes and topside sounders. Hence it constitutes an interesting simulation tool not only serving Galileo needs for mitigation of the ionospheric effect but also widening the use of new data. 相似文献
622.
A. A. Vostrukhin D. V. Golovin A. S. Kozyrev M. L. Litvak A. V. Malakhov I. G. Mitrofanov M. I. Mokrousov T. M. Tomilina Yu. I. Bobrovnitskiy A. S. Grebennikov M. M. Laktionova B. N. Bakhtin A. V. Sotov 《Cosmic Research》2018,56(3):208-212
The results of testing a number of space-based detectors that contain PMTs or high-voltage electrodes for the noise from the microphonics that occurs in the signal path due to external mechanical action have been presented. A method for the vibration isolation of instruments aboard a spacecraft has been proposed to reduce their responsivity to vibrations. 相似文献
623.
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
624.
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
625.
The solution is constructed based on using the general theory of physically orthotropic shells generalizing the Vlasov equations. The numerical results demonstrating the orthotropy influence on the stress strain state are presented. 相似文献
626.
A. Chilingarian V. Babayan T. Karapetyan B. Mailyan B. Sargsyan M. Zazyan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(10):2680-2696
The Space Environment Viewing and Analysis Network (SEVAN) aims to improve the fundamental research on particle acceleration in the vicinity of the sun, on space weather effects and on high-energy physics in the atmosphere and lightning initiation. This new type of a particle detector setup simultaneously measures fluxes of most species of secondary cosmic rays, thus being a powerful integrated device for exploration of solar modulation effects and electron acceleration in the thunderstorm atmosphere. The SEVAN modules are operating at the Aragats Space Environmental Center (ASEC) in Armenia, in Croatia, Bulgaria, Slovakia, the Czech Republic (from 2017) and in India. In this paper, we present the most interesting results of the SEVAN network operation during the last decade. We present this review on the occasion of the 10th anniversary of the International Heliophysical Year in 2007. 相似文献
627.
Based on the experimental data, a dependence of the minimal friction losses in cascades was obtained. A turbine stage efficiency
gain as a result of cascade improvement over the last three decades of the 20th century was estimated by this dependence. 相似文献
628.
B. B. Kreisman 《Cosmic Research》2016,54(6):475-482
Horseshoe orbits in the restricted three-body problem have been mostly considered in the Sun–Jupiter system and, in recent years, in the Sun–Earth system. Here, these orbits have been used to find asteroids that have orbits of this kind. We have built a planar family of horseshoe orbits in the Earth–Moon system and determined the points of planar and 1/1 vertical resonances on this family. We have presented examples of orbits generated by these spatial families. 相似文献
629.
In this paper, a model of heat exchange and resistance in the channels with cylindrical grooves on the walls is presented. We compare the calculated data with the experimental results and give some recommendations for designers of power plants. 相似文献
630.
Atmospheric gravity wave (AGW) is a typical phenomenon in the upper atmosphere. At mid/low latitudes, climatological sources such as unstable barometric activity in the troposphere play an important role to generate AGWs in the thermosphere. While these sources are also important at high latitudes, energy input from the magnetosphere has additional large contributions to AGW generation. This paper reviews previous studies of AGWs associated with auroral activity at high latitudes. Theoretical studies have indicated that Joule/particle heating and the Lorentz force are major processes for generating AGWs in the thermosphere. Many observations show that AGWs can propagate horizontally for thousands of km from the source region. The paper summarizes equations regarding AGW generation by Joule/particle heating and the Lorentz force, and discusses the relative importance of these two processes. 相似文献