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   709453篇
  免费   10279篇
  国内免费   3023篇
电工技术   13710篇
技术理论   5篇
综合类   1676篇
化学工业   108586篇
金属工艺   27550篇
机械仪表   20584篇
建筑科学   17646篇
矿业工程   3652篇
能源动力   18398篇
轻工业   63527篇
水利工程   7248篇
石油天然气   13454篇
武器工业   280篇
无线电   78978篇
一般工业技术   135393篇
冶金工业   138482篇
原子能技术   14072篇
自动化技术   59514篇
  2021年   6688篇
  2020年   4766篇
  2019年   6002篇
  2018年   9975篇
  2017年   9765篇
  2016年   10402篇
  2015年   7585篇
  2014年   12283篇
  2013年   32450篇
  2012年   19899篇
  2011年   27225篇
  2010年   21505篇
  2009年   23597篇
  2008年   24686篇
  2007年   24455篇
  2006年   21440篇
  2005年   19249篇
  2004年   18031篇
  2003年   17526篇
  2002年   16963篇
  2001年   17051篇
  2000年   15864篇
  1999年   16606篇
  1998年   41744篇
  1997年   29605篇
  1996年   22546篇
  1995年   16887篇
  1994年   14928篇
  1993年   14569篇
  1992年   10707篇
  1991年   10057篇
  1990年   9958篇
  1989年   9738篇
  1988年   9042篇
  1987年   7961篇
  1986年   7902篇
  1985年   8789篇
  1984年   8346篇
  1983年   7446篇
  1982年   6925篇
  1981年   7150篇
  1980年   6678篇
  1979年   6709篇
  1978年   6433篇
  1977年   7456篇
  1976年   9867篇
  1975年   5681篇
  1974年   5285篇
  1973年   5440篇
  1972年   4466篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Carstensen and Rhodes1 have suggested that when, in stability programs, assays cannot be performed immediately after the protocol-designated storage time, then freezing them until such a time when assays can be performed would be a reasonable manner to retain the protocol schedule. They caution, however, that such a procedure may not be valid for dissolution data. The article to follow deals with real-time data showing that such a process is feasible for Nalidixic Acid tablets (and presumably for other tablets as well), and that, furthermore, the dissolution pattern would seem to be “frozen” as well.  相似文献   
102.
103.
Abstract This article presents a study of a large scale incorporation of one data acquisitionsystem into physics teaching in Israel. By 1994 about 30% of the schools throughout the country used the V-scope, a 3-D multibody motion tracing system, in their lab programme. The views and reactions of post-training teachers, experienced teachers and students on various aspects of using the system are described, analysed and compared.  相似文献   
104.
Carboxyl-terminated butadiene-acrylonitrile-rubber decreases modulus and yield stress of the studied epoxy but increases fracture toughness. The addition of glass bead compensates for the loss in modulus but has little effect on yield stress. However, it significantly contributes to the fracture toughness by providing additional mechanisms for toughening of both the unmodified and rubber-modified epoxy. For the toughened epoxies studied, fracture surfaces gave only limited information on fracture mechanisms since significant energy absorption also occurs in the material below the fracture surface. Suggestions for suitable material compositions for fiber composite matrices are given.  相似文献   
105.
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   
106.
Gilbenclamide, a widely used potent hypoglycaemic agent was solubllized using β -Cyclodextrin and β -Cyclodextrin derivatives. Complexes were prepared by kneading method in a molar ratio of 1:1 of the drug and the cyclodextrlns respectively. The Glibenclamide β -Cyelocextrin complex was characterized and evaluated by I.R. studies, Differential Scanning Calorimotry 6 X-ray diffractometry. The in-vitro dissolution rates of drug from inclusion complexes of β Cyclodextrins and its derivatives were compared. A significant Improvement In dissolution lor, rates of Gllbenclamide was observed with Inclusion complexes of all the Cyclodextrins. However, the solubilizing effect was more in case of β-Cyclodextrin derivatives.  相似文献   
107.
108.
Functional Properties and Food Applications of Rapeseed Protein Concentrate   总被引:1,自引:0,他引:1  
Rapeseed protein concentrate (RC), prepared with 2% hexameta-phosphate, was tested for its functionality and performance in some foods. The RC had good nitrogen solubility, fat absorption, emulsification, and whipping capacities but poor water absorption and gelling properties. It increased the emulsion stability, and protein but lowered the fat content of wieners. It also increased the cooking yield, reduced the shrinkage and tenderized meat patties. Results were similar to soybean isolate except for the poorer color and flavor. The cooking yield of RC supplemented wieners was less than the all-meat control and soybean-supplemented wieners. A 9% RC dispersion mixed with an equal volume of eggwhite produced a meringue of comparable stability and texture to that of eggwhite alone.  相似文献   
109.
The paper presents the results of research in the convection drying of unidirectional glass fibre bobbins on the basis of which the relations are suggested required to calculate the process of drying in the design of drying equipment.  相似文献   
110.
No generally accepted principles and guidelines currently exist to help engineers design local interaction mechanisms that result in a desired global behavior. However, several communities have developed ways of approaching this problem in the context of niched application areas. Because the ideas underlying these approaches are often obscured or underemphasized in technical papers, the authors review the role of self-organization in their work. They provide a better picture of the status of the emerging field of self-organizing systems or autonomic computing.  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