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   254303篇
  免费   1867篇
  国内免费   274篇
电工技术   4083篇
综合类   97篇
化学工业   41410篇
金属工艺   15270篇
机械仪表   10210篇
建筑科学   4367篇
矿业工程   3775篇
能源动力   3972篇
轻工业   10228篇
水利工程   4114篇
石油天然气   13009篇
武器工业   28篇
无线电   20523篇
一般工业技术   63669篇
冶金工业   33486篇
原子能技术   11173篇
自动化技术   17030篇
  2021年   2850篇
  2019年   2792篇
  2018年   5582篇
  2017年   5859篇
  2016年   6204篇
  2015年   3177篇
  2014年   5462篇
  2013年   10413篇
  2012年   7588篇
  2011年   9223篇
  2010年   7499篇
  2009年   8302篇
  2008年   8427篇
  2007年   8054篇
  2006年   6534篇
  2005年   5732篇
  2004年   5625篇
  2003年   5454篇
  2002年   5241篇
  2001年   5027篇
  2000年   5037篇
  1999年   4337篇
  1998年   7610篇
  1997年   6082篇
  1996年   4597篇
  1995年   3750篇
  1994年   3512篇
  1993年   3723篇
  1992年   3238篇
  1991年   3396篇
  1990年   3502篇
  1989年   3402篇
  1988年   3298篇
  1987年   3284篇
  1986年   3173篇
  1985年   3344篇
  1984年   3271篇
  1983年   3166篇
  1982年   3021篇
  1981年   3085篇
  1980年   3090篇
  1979年   3273篇
  1978年   3514篇
  1977年   3500篇
  1976年   3951篇
  1975年   3228篇
  1974年   3298篇
  1973年   3353篇
  1972年   2996篇
  1971年   2761篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
The technological process of cold forging applied for the first time in the production of the casing of the internal joint with races is described. The process operations of cold forging and the annealing and carburizing regimes for this part me described.  相似文献   
122.
123.
The magnetization of a melt-texture growth (MTG) HTSC ring has been studied. It is shown that the magnetic field inside the ring is larger than the external field under a certain range of external magnetic fields. We have also investigated the magnetic field dependence of the response of a detective coil near a rotating superconducting ring. The responses of the MTG sample are different for different cooling methods.  相似文献   
124.
Comparative analysis of the characteristics of amplitude-dependent internal friction (IF) was carried out to explain reasons leading to an increase of the creep limit of the butt welded joint in PT-3V titanium alloy (PT-2V filler material) after cyclic loading. IF was measured by the method of the direct torsional pendulum on cylindrical specimens representing the gage part of the specimens subjected to preliminary cyclic loading. The data were processed using the Granato-Lucke theory. The results show that the reduction of IF after cyclic loading took place as a result of an increase of the number and redistribution of pinning points of the dislocations. Consequently, the density of mobile dislocations decreases by 8% and the length of dislocation segments by 18%. These processes of stabilization of the structure were completed within 5·10 4 cycles of preliminary loading. Stabilization of the dislocation structure of the material of the welded joint increases its creep limit.Translated from Problemy Prochnosti, No. 4, pp. 35–40, April, 1996.  相似文献   
125.
A method is considered for increasing the immunity from interference of broadband systems for measuring and transmitting information. It is based on utilizing nonlinear methods to process spread-spectrum signals. The possibility is investigated of using a quasioptimal receiving device which can be implemented in practice. It is shown that the proposed method makes it possible to solve the rejection problem at the physical level. Translated from Izmeritel'naya Tekhnika, No. 11, pp. 13–15, November, 1996.  相似文献   
126.
Applications of the additive accumulation of damages (AAD) or the accelerated failure time (AFT) and the proportional hazards (PH) models in accelerated life testing with step-stresses are discussed. A new model including AAD and PH models is proposed. It is more reasonable than the PH model and wider then the AAD model. Constructing the maximum likelihood function is discussed  相似文献   
127.
128.
129.
An efficient algorithm to remove redundant dependences in simple loops with constant dependences is presented. Dependences constrain the parallel execution of programs and are typically enforced by synchronization instructions. The synchronization instructions represent a significant part of the overhead in the parallel execution of a program. Some program dependences are redundant because they are covered by other dependences. It is shown that unlike with single loops, in the case of nested loops, a particular dependence may be redundant at some iterations but not redundant at others, so that the redundancy of a dependence may not be uniform over the entire iteration space. A sufficient condition for the uniformity of redundancy in a doubly nested loop is developed  相似文献   
130.
Translated from Atomnaya Énergiya, Vol. 66, No. 6, pp. 423–424, June, 1989.  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