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   473011篇
  免费   5470篇
  国内免费   1281篇
电工技术   9451篇
综合类   676篇
化学工业   68459篇
金属工艺   16610篇
机械仪表   13188篇
建筑科学   11236篇
矿业工程   1542篇
能源动力   12369篇
轻工业   41782篇
水利工程   3931篇
石油天然气   6115篇
武器工业   15篇
无线电   61741篇
一般工业技术   88898篇
冶金工业   96333篇
原子能技术   8235篇
自动化技术   39181篇
  2021年   3268篇
  2019年   3181篇
  2018年   5298篇
  2017年   5180篇
  2016年   5344篇
  2015年   3801篇
  2014年   6545篇
  2013年   20853篇
  2012年   10957篇
  2011年   15109篇
  2010年   11986篇
  2009年   13859篇
  2008年   14604篇
  2007年   14536篇
  2006年   13075篇
  2005年   12181篇
  2004年   11986篇
  2003年   11673篇
  2002年   11323篇
  2001年   11814篇
  2000年   11166篇
  1999年   11997篇
  1998年   31058篇
  1997年   21599篇
  1996年   16816篇
  1995年   12744篇
  1994年   11395篇
  1993年   11130篇
  1992年   8035篇
  1991年   7739篇
  1990年   7534篇
  1989年   7288篇
  1988年   6957篇
  1987年   5753篇
  1986年   5948篇
  1985年   6880篇
  1984年   6169篇
  1983年   5692篇
  1982年   5171篇
  1981年   5492篇
  1980年   4941篇
  1979年   4773篇
  1978年   4596篇
  1977年   5499篇
  1976年   7200篇
  1975年   3950篇
  1974年   3795篇
  1973年   3760篇
  1972年   3141篇
  1971年   2764篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Given the enormous size of the genome and that there are potentially many other types of measurements we need to do to understand it, it has become necessary to pick and choose one's targets to measure because it is still impossible to evaluate the entire genome all at once. What has emerged is a need to have rapidly customizable microarrays. There are two dominant methods to accomplish custom microarray synthesis, Affymetrix-like microarrays manufactured using light projection rather than semiconductor-like masks used by Affymetrix to mass manufacture their GeneChip/sup TM/ arrays now, or the ink-jet printing method employed by Agilent. The manufacture of these custom Affymetrix-like microarrays can now be done on a digital optical chemistry (DOC) machine developed at the University of Texas Southwestern Medical Center, and this method offers much higher feature numbers and feature density than is possible with ink-jet printed arrays. On a microarray, each feature contains a single genetic measurement. The initial DOC prototype has been described in several publications, but that has now led to a second-generation machine. This machine reliably produces a number of arrays daily, has been deployed against a number of biomedical questions, is being used in new ways and has also led to a number of spin-off technologies.  相似文献   
93.
94.
A series of small angle neutron scattering measurements on blends of normal polystyrene (PSH) and labelled (deuterated) polystyrene (PSD) have been made with concentrations of PSD from 5 to 50 mol %. It is shown that the single chain form factor of the polymer in bulk can be obtained from a single concentration measurement for any concentration of labelled molecules, providing the molecular weights of the parent and labelled molecules are the same and the molecular weight distributions are narrow.  相似文献   
95.
96.
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   
97.
Translated from Atomnaya Énergiya, Vol. 67, No. 3, pp. 215–216, September, 1989.  相似文献   
98.
99.
Blends of lard with eight separate fats or oils (70:30 w/w) were prepared and used as the fat component of meat batters. After cooking, the batters were analyzed for water and fat exudation and gel strength. None differed significantly from the control of 100% lard. Positive correlation coefficients, however, were significant between percent monounsaturated triglycerides and water exudation, polyunsaturated triglycerides and fat exudation and saturated triglycerides and gel strength. Addition of lecithin, cholesterol or methyl palmitate to the lard increased fat exudation and decreased gel strength. Sodium laurate had the opposite effect whether added to the lard or to the aqueous phase.  相似文献   
100.
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