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   1633973篇
  免费   27306篇
  国内免费   7154篇
电工技术   35161篇
综合类   6537篇
化学工业   279728篇
金属工艺   66345篇
机械仪表   46532篇
建筑科学   49728篇
矿业工程   11789篇
能源动力   51036篇
轻工业   128074篇
水利工程   16481篇
石油天然气   38157篇
武器工业   154篇
无线电   201218篇
一般工业技术   304561篇
冶金工业   220178篇
原子能技术   34535篇
自动化技术   178219篇
  2021年   16049篇
  2020年   12324篇
  2019年   15158篇
  2018年   18839篇
  2017年   18228篇
  2016年   23301篇
  2015年   18133篇
  2014年   29430篇
  2013年   89666篇
  2012年   39417篇
  2011年   54352篇
  2010年   46195篇
  2009年   53727篇
  2008年   49931篇
  2007年   47710篇
  2006年   47865篇
  2005年   43325篇
  2004年   44560篇
  2003年   44193篇
  2002年   42858篇
  2001年   39793篇
  2000年   37726篇
  1999年   37768篇
  1998年   62062篇
  1997年   49903篇
  1996年   42278篇
  1995年   34866篇
  1994年   32040篇
  1993年   32049篇
  1992年   27296篇
  1991年   24521篇
  1990年   24736篇
  1989年   23883篇
  1988年   22410篇
  1987年   20527篇
  1986年   19893篇
  1985年   23248篇
  1984年   22954篇
  1983年   20885篇
  1982年   19759篇
  1981年   19957篇
  1980年   18581篇
  1979年   18901篇
  1978年   18207篇
  1977年   18903篇
  1976年   21396篇
  1975年   16348篇
  1974年   15732篇
  1973年   15865篇
  1972年   13331篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
This paper presents part of the work ComEd and Quanta Technology have performed to quantify the locational and temporal value of DER to avoid distribution grid upgrade investments. It focuses on the formulation of a robust and efficient algorithm for DER optimal dispatch on a distribution feeder to mitigate the violation of current and voltage limits using the allocated cost of capacity and locational marginal value of real and reactive DER injection/withdrawal.  相似文献   
2.
3.
Russian Engineering Research - Models based on regression analysis for predicting the operational efficiency of high-pressure roller crushers are considered. A systematized and structured...  相似文献   
4.
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   
5.
Journal of Machinery Manufacture and Reliability - The problem of calculating the reliability and fatigue life of machine parts by the fatigue failure under random changes in the actual and limit...  相似文献   
6.
In this paper, we present a novel memory access reduction scheme (MARS) for two-dimension fast cosine transform (2-D FCT). It targets programmable DSPs with high memory-access latency. It reduces the number of memory accesses by: 1) reducing the number of weighting factors and 2) combining butterflies in vector-radix 2-D FCT pruning diagram from two stages to one stage with an efficient structure. Hardware platform based on general purpose processor is used to verify the effectiveness of the proposed method for vector-radix 2-D FCT pruning implementation. Experimental results validate the benefits of the proposed method with reduced memory access, less clock cycle and fewer memory space compared with the conventional implementation.  相似文献   
7.
8.
9.
One specific class of non-linear evolution equations, known as the Tzitzéica-type equations, has received great attention from a group of researchers involved in non-linear science. In this article, new exact solutions of the Tzitzéica-type equations arising in non-linear optics, including the Tzitzéica, Dodd–Bullough–Mikhailov and Tzitzéica–Dodd–Bullough equations, are obtained using the expa function method. The integration technique actually suggests a useful and reliable method to extract new exact solutions of a wide range of non-linear evolution equations.  相似文献   
10.
ABSTRACT

Bacteriocin is a proteinaceous biomolecule produced by bacteria (both Gram-positive and Gram-negative) that exhibits antimicrobial activity against closely related species, and food-borne pathogens. It has recently gained importance and attracted the attention of several researchers looking to produce it from various substrates and bacterial strains. This ushers in a new era of food preservation where the use of bacteriocin in food products will be an alternative to chemical preservatives, and heat treatment which are understood to cause unwanted side effects, and reduce sensory and nutritional quality. However, this new market depends on the success of novel downstream separation schemes from various types of crude feedstocks which are both effective and economic. This review focuses on the downstream separation of bacteriocin from various sources using both conventional and novel techniques. Finally, recommendations for future interesting areas of research that need to be pursued are highlighted.  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