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   1579838篇
  免费   27219篇
  国内免费   7074篇
电工技术   35342篇
综合类   6461篇
化学工业   279390篇
金属工艺   66172篇
机械仪表   46169篇
建筑科学   48116篇
矿业工程   11885篇
能源动力   50835篇
轻工业   122188篇
水利工程   16057篇
石油天然气   38414篇
武器工业   152篇
无线电   200190篇
一般工业技术   297847篇
冶金工业   184193篇
原子能技术   34666篇
自动化技术   176054篇
  2021年   16244篇
  2020年   12387篇
  2019年   15250篇
  2018年   19508篇
  2017年   19229篇
  2016年   23603篇
  2015年   18197篇
  2014年   29427篇
  2013年   89402篇
  2012年   38641篇
  2011年   53412篇
  2010年   46363篇
  2009年   54200篇
  2008年   48793篇
  2007年   46605篇
  2006年   46444篇
  2005年   42165篇
  2004年   43383篇
  2003年   43066篇
  2002年   41808篇
  2001年   38210篇
  2000年   36553篇
  1999年   35703篇
  1998年   50870篇
  1997年   43063篇
  1996年   37691篇
  1995年   32164篇
  1994年   29907篇
  1993年   29784篇
  1992年   26544篇
  1991年   23746篇
  1990年   24055篇
  1989年   23149篇
  1988年   21650篇
  1987年   19882篇
  1986年   19243篇
  1985年   22569篇
  1984年   22537篇
  1983年   20524篇
  1982年   19453篇
  1981年   19552篇
  1980年   18189篇
  1979年   18638篇
  1978年   17897篇
  1977年   18006篇
  1976年   19434篇
  1975年   16120篇
  1974年   15591篇
  1973年   15721篇
  1972年   13159篇
排序方式: 共有10000条查询结果,搜索用时 0 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