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   1567507篇
  免费   26219篇
  国内免费   7074篇
电工技术   35288篇
综合类   6470篇
化学工业   276501篇
金属工艺   66218篇
机械仪表   45848篇
建筑科学   48131篇
矿业工程   11920篇
能源动力   50746篇
轻工业   119683篇
水利工程   15906篇
石油天然气   38400篇
武器工业   147篇
无线电   200033篇
一般工业技术   296482篇
冶金工业   179973篇
原子能技术   34685篇
自动化技术   174369篇
  2021年   15659篇
  2020年   11960篇
  2019年   14779篇
  2018年   18710篇
  2017年   18525篇
  2016年   22849篇
  2015年   17614篇
  2014年   28848篇
  2013年   88605篇
  2012年   37799篇
  2011年   52667篇
  2010年   45855篇
  2009年   53811篇
  2008年   48432篇
  2007年   46388篇
  2006年   46421篇
  2005年   42205篇
  2004年   43423篇
  2003年   43127篇
  2002年   41928篇
  2001年   38186篇
  2000年   36533篇
  1999年   35631篇
  1998年   49411篇
  1997年   42104篇
  1996年   37178篇
  1995年   31891篇
  1994年   29703篇
  1993年   29546篇
  1992年   26539篇
  1991年   23673篇
  1990年   24031篇
  1989年   23120篇
  1988年   21626篇
  1987年   19857篇
  1986年   19233篇
  1985年   22617篇
  1984年   22580篇
  1983年   20564篇
  1982年   19484篇
  1981年   19540篇
  1980年   18157篇
  1979年   18670篇
  1978年   17882篇
  1977年   17847篇
  1976年   19015篇
  1975年   16142篇
  1974年   15601篇
  1973年   15710篇
  1972年   13178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.
In this study, amaranth flour was used as an ingredient to prepare gluten-free cookies. The production process and attributes of amaranth cookies were characterised, and the potential use of amaranth flour as a functional ingredient was analysed. Cookies exhibited a non-uniform reddish brown colour and a cookie factor ratio of 4.5 ± 0.6. Storage studies indicated that after 3 weeks at room temperature cookies presented slight variations in the texture. Simulated gastrointestinal digestion of this product was able to release peptides capable of exerting potential antithrombotic and antihypertensive activities, IC50 values of 0.22 ± 0.04 and 0.23 ± 0.03 mg mL−1 protein, respectively. This work demonstrates for the first time that food made with amaranth flour exerts potential antithrombotic and antihypertensive activity. In conclusion, these amaranth cookies could be an alternative way of incorporating potentially health beneficial products for people who choose a conscious diet, including coeliac or vegan consumers.  相似文献   
9.
10.
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   
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