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   401440篇
  免费   3619篇
  国内免费   949篇
电工技术   6881篇
综合类   192篇
化学工业   64283篇
金属工艺   21643篇
机械仪表   14306篇
建筑科学   8252篇
矿业工程   4226篇
能源动力   8198篇
轻工业   24849篇
水利工程   5364篇
石油天然气   14769篇
武器工业   30篇
无线电   37957篇
一般工业技术   90509篇
冶金工业   61425篇
原子能技术   13842篇
自动化技术   29282篇
  2021年   3853篇
  2019年   3749篇
  2018年   7070篇
  2017年   7335篇
  2016年   7730篇
  2015年   4381篇
  2014年   7546篇
  2013年   17066篇
  2012年   11170篇
  2011年   14468篇
  2010年   11621篇
  2009年   13189篇
  2008年   13274篇
  2007年   12923篇
  2006年   10738篇
  2005年   9664篇
  2004年   9390篇
  2003年   8916篇
  2002年   8753篇
  2001年   8613篇
  2000年   8383篇
  1999年   7891篇
  1998年   16680篇
  1997年   12591篇
  1996年   9624篇
  1995年   7550篇
  1994年   6752篇
  1993年   6859篇
  1992年   5532篇
  1991年   5557篇
  1990年   5582篇
  1989年   5460篇
  1988年   5305篇
  1987年   5045篇
  1986年   4898篇
  1985年   5345篇
  1984年   5120篇
  1983年   4823篇
  1982年   4550篇
  1981年   4693篇
  1980年   4557篇
  1979年   4706篇
  1978年   4887篇
  1977年   5188篇
  1976年   6181篇
  1975年   4398篇
  1974年   4433篇
  1973年   4540篇
  1972年   3985篇
  1971年   3672篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
103.
104.
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   
105.
106.
Incremental transmission loss analysis has been used for decades, but recent interest in its application to loss allocation calls for new in-depth results. This paper demonstrates that, for incremental methods to be applied correctly in loss allocation, it is first necessary to specify the load distribution and loss supply strategies. Incremental loss allocation among bus power injections is shown to be arbitrary and, therefore, open to challenge as discriminatory. Loss allocation is possible among incremental loads and/or generators, but the proportion of the total losses assigned to either one is arbitrary. Unique, nonarbitrary incremental loss allocations are however possible among the "equivalent" incremental bilateral exchanges between generators and loads. From these basic components it is possible then to calculate the allocation among generators or loads in any specified proportion. The main results, although developed initially for small increments, are extended to large variations. Finally, a general incremental loss allocation algorithm is developed and tested  相似文献   
107.
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   
108.
The article presents the results of experimental investigations of critical (limit) heat fluxes upon evaporation on porous coatings, and it substantiates the physical model of the process.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 4, pp. 607–614, October, 1985.  相似文献   
109.
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   
110.
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   
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