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   3005篇
  免费   29篇
  国内免费   1篇
电工技术   50篇
综合类   1篇
化学工业   517篇
金属工艺   240篇
机械仪表   188篇
建筑科学   17篇
矿业工程   60篇
能源动力   41篇
轻工业   67篇
水利工程   37篇
石油天然气   135篇
无线电   207篇
一般工业技术   838篇
冶金工业   328篇
原子能技术   162篇
自动化技术   147篇
  2022年   39篇
  2021年   68篇
  2020年   40篇
  2019年   39篇
  2018年   76篇
  2017年   81篇
  2016年   97篇
  2015年   58篇
  2014年   67篇
  2013年   95篇
  2012年   96篇
  2011年   117篇
  2010年   99篇
  2009年   94篇
  2008年   96篇
  2007年   93篇
  2006年   80篇
  2005年   66篇
  2004年   52篇
  2003年   42篇
  2002年   74篇
  2001年   51篇
  2000年   58篇
  1999年   45篇
  1998年   50篇
  1997年   62篇
  1995年   38篇
  1993年   35篇
  1992年   28篇
  1991年   36篇
  1990年   36篇
  1989年   43篇
  1988年   38篇
  1986年   33篇
  1985年   33篇
  1984年   35篇
  1983年   40篇
  1982年   31篇
  1981年   29篇
  1980年   32篇
  1978年   43篇
  1977年   54篇
  1976年   46篇
  1975年   40篇
  1974年   46篇
  1973年   49篇
  1972年   37篇
  1971年   46篇
  1969年   39篇
  1967年   30篇
排序方式: 共有3035条查询结果,搜索用时 62 毫秒
1.
Journal of Machinery Manufacture and Reliability - A device based on smart alloys has been designed for use in machine building items, in particular, in nuclear engineering, for preventing...  相似文献   
2.
3.
4.
5.
It was shown that use of AS32–AS50 diamond powders (instead of AS6–AS15 powders) combined with a new metal bond with hardness of HB 75–85 (in comparison to M2-01 binder) allows prolonging the lifetime of wheels by 1.5–2 times in grinding articles made of commercial and art glass, reducing the specific diamond consumption, and increasing the cutability of the instrument.  相似文献   
6.
This paper analyses the load influence on a d.c. drive motor servo system for all six degrees of freedom of industrial robots with an articulated configuration. Through the analyses, the analytical equations of total inertia and gravitation moments of an industrial robot servo system for external coordinate function were obtained. A mathematical model of an electro-mechanical industrial robot system was also developed.  相似文献   
7.
This paper evaluates different forms of rank-based selection that are used with genetic algorithms and genetic programming. Many types of rank based selection have exactly the same expected value in terms of the sampling rate allocated to each member of the population. However, the variance associated with that sampling rate can vary depending on how selection is implemented. We examine two forms of tournament selection and compare these to linear rank-based selection using an explicit formula. Because selective pressure has a direct impact on population diversity, we also examine the interaction between selective pressure and different mutation strategies.  相似文献   
8.
The possibilities of using influenza A (Leningrad) 385/80 (H3N2) virus matrix protein-specific FITC-labeled D8 monoclonal antibodies in immunofluorescence assays were investigated. The virus antigen accumulation was detected in chorioallantoic cells of chick embryos. Exhibiting the type-specific properties, the fluorescent antibodies stain the perinuclear space, cytoplasmic membrane, and granular structures in the cytoplasm of infected cells. The haemagglutination test tires in the corresponding specimens were at least 1:16.  相似文献   
9.
The characteristic features of the continuous-wave lasing spectra near 3.3 μm of multimode InAsSbP/InAsSb/InAsSbP double-heterostructure diode lasers are shown. The observation of mode switching to longer and shorter wavelengths at cryogenic temperatures is reported. It is shown that suppression of the longitudinal side modes closest to the main mode results in large mode jumps in energy during mode tuning by current. The characteristics which were observed are explained by gain spectrum inhomogeneity due to spectral hole burning in narrow-gap semiconductors. The intraband charge-carrier relaxation times in the active region are estimated. Fiz. Tekh. Poluprovodn. 39, 1139–1144 (September 1998)  相似文献   
10.
By measuring electroluminescence (EL) in barium titanate crystals exposed to a pulsed electric field in combination with a magnetic field, we have studied the dependence of a shift in the temperature of maximum EL on the magnetic field strength and on the mutual orientation of the electric and magnetic fields. The possible mechanisms of the observed effects are discussed.  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