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   1504588篇
  免费   34570篇
  国内免费   6985篇
电工技术   34763篇
综合类   6376篇
化学工业   280064篇
金属工艺   63871篇
机械仪表   41651篇
建筑科学   46555篇
矿业工程   11320篇
能源动力   50784篇
轻工业   113401篇
水利工程   14908篇
石油天然气   37426篇
武器工业   132篇
无线电   199964篇
一般工业技术   285321篇
冶金工业   154833篇
原子能技术   33867篇
自动化技术   170907篇
  2021年   15863篇
  2020年   12861篇
  2019年   16815篇
  2018年   17252篇
  2017年   16776篇
  2016年   23501篇
  2015年   19714篇
  2014年   31021篇
  2013年   91082篇
  2012年   36204篇
  2011年   47862篇
  2010年   43398篇
  2009年   51806篇
  2008年   44829篇
  2007年   41486篇
  2006年   44808篇
  2005年   39082篇
  2004年   41551篇
  2003年   41476篇
  2002年   40471篇
  2001年   37238篇
  2000年   35879篇
  1999年   34636篇
  1998年   42457篇
  1997年   37458篇
  1996年   34179篇
  1995年   30060篇
  1994年   28407篇
  1993年   28222篇
  1992年   25920篇
  1991年   23010篇
  1990年   23332篇
  1989年   22400篇
  1988年   20936篇
  1987年   19213篇
  1986年   18596篇
  1985年   21832篇
  1984年   22163篇
  1983年   20143篇
  1982年   19194篇
  1981年   19296篇
  1980年   17879篇
  1979年   18412篇
  1978年   17638篇
  1977年   17303篇
  1976年   18159篇
  1975年   15935篇
  1974年   15437篇
  1973年   15510篇
  1972年   12974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.
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   
4.
5.
6.
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   
7.
8.
Clean Technologies and Environmental Policy - Food production and consumption is one of the major causes of global environmental degradation. One way to address environmental impacts in the food...  相似文献   
9.
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   
10.
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