首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3701篇
  免费   7篇
  国内免费   5篇
航空   1510篇
航天技术   1038篇
综合类   19篇
航天   1146篇
  2022年   15篇
  2021年   37篇
  2019年   16篇
  2018年   205篇
  2017年   163篇
  2016年   129篇
  2015年   48篇
  2014年   112篇
  2013年   134篇
  2012年   132篇
  2011年   217篇
  2010年   190篇
  2009年   250篇
  2008年   236篇
  2007年   188篇
  2006年   74篇
  2005年   124篇
  2004年   98篇
  2003年   106篇
  2002年   83篇
  2001年   115篇
  2000年   36篇
  1999年   53篇
  1998年   61篇
  1997年   42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3713条查询结果,搜索用时 15 毫秒
841.
842.
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   
843.
We consider a probabilistic estimation of microaccelerations being produced in the inboard environment of an orbital laboratory as a random process; based on this estimation we analyzed a probability of fulfilling the favorable conditions to realize gravity-sensitive processes. The approach suggested can be applied when designing a space laboratory to meet the requirements for the microaccelerations inside the working zone of technological equipment.  相似文献   
844.
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   
845.
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   
846.
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   
847.
848.
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   
849.
This paper proposes to solve the problem of determining the strength properties of materials for thin-walled structural elements under mechanical and thermal loading as an optimization problem. A mathematical statement of the problem under certain assumptions is given.  相似文献   
850.
A computational technique, developed for analysis of strength, stability and low-cycle durability of GTE exhaust frame complex structure under operational and emergency loads is described. The presented technique, based on the ANSYS and STAR-CD engineering analysis software, and self-design software can improve the accuracy and efficiency of calculations, and reduce efforts on finite element mesh development, performing calculations and processing of results.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号