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   269683篇
  免费   4625篇
  国内免费   456篇
电工技术   4499篇
综合类   274篇
化学工业   45272篇
金属工艺   9924篇
机械仪表   7997篇
建筑科学   6272篇
矿业工程   1454篇
能源动力   5645篇
轻工业   29597篇
水利工程   2751篇
石油天然气   5182篇
武器工业   37篇
无线电   26135篇
一般工业技术   49575篇
冶金工业   51776篇
原子能技术   6069篇
自动化技术   22305篇
  2021年   2811篇
  2020年   2084篇
  2019年   2701篇
  2018年   4690篇
  2017年   4593篇
  2016年   4933篇
  2015年   3191篇
  2014年   5002篇
  2013年   12509篇
  2012年   7874篇
  2011年   9845篇
  2010年   7829篇
  2009年   8374篇
  2008年   8673篇
  2007年   8737篇
  2006年   7566篇
  2005年   6636篇
  2004年   6359篇
  2003年   6094篇
  2002年   6151篇
  2001年   5890篇
  2000年   5702篇
  1999年   5656篇
  1998年   14445篇
  1997年   10173篇
  1996年   7666篇
  1995年   5836篇
  1994年   5123篇
  1993年   5094篇
  1992年   3848篇
  1991年   3566篇
  1990年   3724篇
  1989年   3599篇
  1988年   3441篇
  1987年   3014篇
  1986年   3033篇
  1985年   3495篇
  1984年   3335篇
  1983年   2973篇
  1982年   2858篇
  1981年   2945篇
  1980年   2846篇
  1979年   2692篇
  1978年   2757篇
  1977年   3185篇
  1976年   4351篇
  1975年   2415篇
  1974年   2286篇
  1973年   2429篇
  1972年   1989篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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   
2.
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   
3.
4.
5.
6.
7.
A layer-by-layer analysis of the structures, the phase compositions, and the defect substructures of differentially hardened rails has been carried by optical and transmission electron microscopy. It is found that the material volume of the rail head fillet is cooled faster than the volume located along the central axis.  相似文献   
8.
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product.  相似文献   
9.
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