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   1596427篇
  免费   33864篇
  国内免费   11135篇
电工技术   39656篇
技术理论   6篇
综合类   12518篇
化学工业   284914篇
金属工艺   69864篇
机械仪表   48469篇
建筑科学   53626篇
矿业工程   14715篇
能源动力   52896篇
轻工业   115995篇
水利工程   16943篇
石油天然气   44100篇
武器工业   946篇
无线电   205510篇
一般工业技术   290848篇
冶金工业   176399篇
原子能技术   34755篇
自动化技术   179266篇
  2022年   13213篇
  2021年   19668篇
  2020年   15031篇
  2019年   17090篇
  2018年   17471篇
  2017年   17018篇
  2016年   23649篇
  2015年   21237篇
  2014年   33327篇
  2013年   93226篇
  2012年   40745篇
  2011年   52773篇
  2010年   47075篇
  2009年   55202篇
  2008年   48795篇
  2007年   45459篇
  2006年   49360篇
  2005年   43091篇
  2004年   43767篇
  2003年   43591篇
  2002年   42589篇
  2001年   39568篇
  2000年   37863篇
  1999年   37558篇
  1998年   49411篇
  1997年   42189篇
  1996年   38112篇
  1995年   32696篇
  1994年   30439篇
  1993年   29864篇
  1992年   26747篇
  1991年   23844篇
  1990年   24032篇
  1989年   23078篇
  1988年   21477篇
  1987年   19681篇
  1986年   19012篇
  1985年   22262篇
  1984年   22356篇
  1983年   20333篇
  1982年   19360篇
  1981年   19439篇
  1980年   18027篇
  1979年   18545篇
  1978年   17814篇
  1977年   17741篇
  1976年   19288篇
  1975年   16037篇
  1974年   15531篇
  1973年   15597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.
With the emergence of large-scale knowledge base, how to use triple information to generate natural questions is a key technology in question answering systems. The traditional way of generating questions require a lot of manual intervention and produce lots of noise. To solve these problems, we propose a joint model based on semi-automated model and End-to-End neural network to automatically generate questions. The semi-automated model can generate question templates and real questions combining the knowledge base and center graph. The End-to-End neural network directly sends the knowledge base and real questions to BiLSTM network. Meanwhile, the attention mechanism is utilized in the decoding layer, which makes the triples and generated questions more relevant. Finally, the experimental results on SimpleQuestions demonstrate the effectiveness of the proposed approach.  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.
The severe environmental pollution in many countries is caused by indiscriminate discharge of large quantities of food waste (FW), fat oil and grease (FOG) and sewage sludge (SS) to the environment. There are many possible treatment routes, but anaerobic digestion (AD) is now well accepted for treating several kinds of organic wastes. But AD of FW alone presents some operational challenges because of substrates and variability. Anaerobic co-digestion of two or more substrates is better than single substrate digestion. This can use a plant’s unused capacity, in line with the trend to renewable energy. Co-digestion technology, although well established in many European countries, is still in its infancy in Ireland. There are problems with different regulatory arrangements. They should be resolved. The paper reviews anaerobic co-digestion technology is reviewed, with special focus on possible application in Ireland.  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