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   1693378篇
  免费   28357篇
  国内免费   8086篇
电工技术   36469篇
技术理论   5篇
综合类   7611篇
化学工业   282884篇
金属工艺   67848篇
机械仪表   48901篇
建筑科学   50494篇
矿业工程   12290篇
能源动力   50949篇
轻工业   134561篇
水利工程   17347篇
石油天然气   39151篇
武器工业   391篇
无线电   203617篇
一般工业技术   313304篇
冶金工业   249752篇
原子能技术   34745篇
自动化技术   179502篇
  2021年   16422篇
  2020年   12563篇
  2019年   15269篇
  2018年   20146篇
  2017年   19703篇
  2016年   23987篇
  2015年   18569篇
  2014年   29772篇
  2013年   89781篇
  2012年   41457篇
  2011年   57591篇
  2010年   48154篇
  2009年   55261篇
  2008年   52447篇
  2007年   50837篇
  2006年   49644篇
  2005年   44956篇
  2004年   45611篇
  2003年   45088篇
  2002年   43494篇
  2001年   40943篇
  2000年   38881篇
  1999年   39483篇
  1998年   72061篇
  1997年   55714篇
  1996年   45932篇
  1995年   36923篇
  1994年   33754篇
  1993年   33744篇
  1992年   27709篇
  1991年   24967篇
  1990年   25214篇
  1989年   24313篇
  1988年   22874篇
  1987年   20972篇
  1986年   20417篇
  1985年   23652篇
  1984年   23131篇
  1983年   21047篇
  1982年   19862篇
  1981年   20102篇
  1980年   18722篇
  1979年   19029篇
  1978年   18278篇
  1977年   19250篇
  1976年   22373篇
  1975年   16394篇
  1974年   15826篇
  1973年   15957篇
  1972年   13387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.
Qin  Yi  Tao  Xianping  Huang  Yu    Jian 《World Wide Web》2019,22(1):1-37
World Wide Web - Rule mechanism has been widely used in many areas, such as databases, artificial intelligent and pervasive computing. In a rule mechanism, rule activation decides which rules are...  相似文献   
7.
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   
8.
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