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   250144篇
  免费   1691篇
  国内免费   268篇
电工技术   4049篇
综合类   91篇
化学工业   40629篇
金属工艺   15183篇
机械仪表   10078篇
建筑科学   4184篇
矿业工程   3759篇
能源动力   3920篇
轻工业   9767篇
水利工程   4088篇
石油天然气   13009篇
武器工业   28篇
无线电   20282篇
一般工业技术   63080篇
冶金工业   32248篇
原子能技术   11146篇
自动化技术   16562篇
  2021年   2778篇
  2019年   2749篇
  2018年   5456篇
  2017年   5738篇
  2016年   6087篇
  2015年   3065篇
  2014年   5351篇
  2013年   10162篇
  2012年   7352篇
  2011年   8984篇
  2010年   7336篇
  2009年   8157篇
  2008年   8225篇
  2007年   7906篇
  2006年   6397篇
  2005年   5601篇
  2004年   5508篇
  2003年   5328篇
  2002年   5175篇
  2001年   4978篇
  2000年   4955篇
  1999年   4276篇
  1998年   7214篇
  1997年   5859篇
  1996年   4452篇
  1995年   3674篇
  1994年   3441篇
  1993年   3642篇
  1992年   3220篇
  1991年   3371篇
  1990年   3497篇
  1989年   3377篇
  1988年   3279篇
  1987年   3280篇
  1986年   3171篇
  1985年   3327篇
  1984年   3258篇
  1983年   3155篇
  1982年   2997篇
  1981年   3056篇
  1980年   3084篇
  1979年   3260篇
  1978年   3495篇
  1977年   3463篇
  1976年   3917篇
  1975年   3212篇
  1974年   3294篇
  1973年   3346篇
  1972年   2988篇
  1971年   2756篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
In this paper, effects of particles on the subgrid scales of turbulence are properly accounted for during the modeling of subgrid scale stresses in the large-eddy simulation (LES) of fluid phase. In doing so, we propose closed filtered kinetic equations for phase space density of the particle. The various moments of these equations give the `fluid' equations which can be considered as the LES equations for the particle phase. The influence of subgrid scales motion on the particles is included in these `fluid' equations.  相似文献   
102.
103.
104.
The mean convergence of various versions of a genetic algorithm are considered. A number of convergence statements are formulated and relevant estimates are obtained. A hypothesis concerning the form of these estimates under variation of the structure of a genetic algorithm is put forward. Roman Riviyanovich Sharapov. Born 1981. Graduated from the Faculty of Mechanics and Mathematics, Ural State University, in 2003. Presently, a postgraduate at the Department of Mathematical Economics at the same university. Scientific interests: genetic algorithms, neural networks, and financial mathematics. Aleksandr Vyacheslavovich Lapshin. Born 1980. Graduated from the Faculty of Mechanics and Mathematics, Ural State University, in 2003. Presently, a postgraduate at the Department of Mathematical Economics at the same university. Scientific interests: financial mathematics, genetic algorithms, and neural networks.  相似文献   
105.
106.
Validity on the well-known Onsager reciprocal relations L 12=L 21 is verified in the kinetic theory of gases taking into account mass and heat transfer near the surface. Using an analytical solution to the ellipsoidal statistical equation (providing for the true Prandtl number), it is demonstrated that the Onsager relations are obeyed, at least to within exponential corrections of the type exp(−1/Kn) in the Knudsen number.  相似文献   
107.
It is established that the capillary rise of a liquid has an oscillatory character, in contrast to the commonly accepted opinion that a vertical capillary is filled at a monotonically varying velocity. The value of the tangential shear stress arising in an ascending liquid is evaluated for ethyl alcohol and distilled water.  相似文献   
108.
The purpose and current construction status, at the Institute of Theoretical and Experimental Physics, of an experimental electronuclear setup, combining a pulsed proton linear accelerator (36 MeV, 0.5 mA) and a subcritical blanket thermal-power assembly 100 kW, are discussed. The main equipment is already available or is being built in industry. The setup can be used to investigate the dynamics of the interaction of a linac–driver and a subcritical reactor and problems concerning the accelerator–driver and the target–blanket assembly. The proton beams and neutron fluxes will be used for applied purposes. In the future it will be possible to increase substantially the current and energy of the proton beam.  相似文献   
109.
A.V. Kolobov  P. Fons 《Thin solid films》2007,515(19):7534-7537
We discuss specific features of Te-based compounds that made them the best materials for the phase-change data storage. It is demonstrated that the phase-change recording is due to a switch of Ge atoms between octahedral and tetrahedral symmetry positions within the Te face-centered cubic lattice. It is this nature of the transition that makes the Te-based media fast and stable. The driving force for this transition is also discussed. The chapter is concluded by introduction of a concept of the super-resolution near-field structure (super-RENS) disc that allows to reduce a bit size well below the diffraction limit and makes 100 GB/disc storage a reality.  相似文献   
110.
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