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   15544篇
  免费   1178篇
  国内免费   14篇
电工技术   150篇
综合类   12篇
化学工业   3948篇
金属工艺   200篇
机械仪表   419篇
建筑科学   666篇
矿业工程   39篇
能源动力   422篇
轻工业   2998篇
水利工程   131篇
石油天然气   37篇
无线电   1083篇
一般工业技术   2812篇
冶金工业   776篇
原子能技术   51篇
自动化技术   2992篇
  2024年   52篇
  2023年   199篇
  2022年   352篇
  2021年   581篇
  2020年   425篇
  2019年   465篇
  2018年   654篇
  2017年   645篇
  2016年   727篇
  2015年   591篇
  2014年   766篇
  2013年   1392篇
  2012年   1324篇
  2011年   1245篇
  2010年   839篇
  2009年   807篇
  2008年   866篇
  2007年   771篇
  2006年   608篇
  2005年   452篇
  2004年   423篇
  2003年   354篇
  2002年   341篇
  2001年   191篇
  2000年   184篇
  1999年   126篇
  1998年   154篇
  1997年   140篇
  1996年   105篇
  1995年   116篇
  1994年   90篇
  1993年   79篇
  1992年   52篇
  1991年   53篇
  1990年   38篇
  1989年   40篇
  1988年   34篇
  1987年   20篇
  1986年   28篇
  1985年   39篇
  1984年   44篇
  1983年   29篇
  1982年   24篇
  1981年   27篇
  1980年   22篇
  1979年   33篇
  1978年   17篇
  1977年   15篇
  1976年   14篇
  1975年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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   
2.
3.
4.
5.
6.
7.
Software and Systems Modeling - Many model transformation scenarios require flexible execution strategies as they should produce models with the highest possible quality. At the same time,...  相似文献   
8.
This paper discusses the convenience of using two-dimensional (2-D) coding techniques for the compression of electrocardiogram (ECG) signals. These signals present a very clear periodicity that can be exploited by the use of a 2-D time/frequency transform to decorrelate it as much as possible. A brief theoretical approach is given to justify the use of this technique, and a comparison is made between a 2-D and a one-dimensional (1-D) uniform quantization scenarios. The influence of the error as well as the frame size on the estimation of the fundamental period is studied.  相似文献   
9.
Studied how 26 senior managers and 47 senior professional technical staff (recently repatriated) of 4 US owned multinational organizations viewed their international posting, specifically with respect to career path satisfaction. Results of satisfaction scales indicate that many Ss felt under-prepared for their international assignment. It is suggested that a comprehensive international employee development program should assess, provide feedback, and coach individuals on career path, culture shock and adjustment, and performance issues prior, during, and on return from the expatriate assignment. Results suggest that opportunities exist for individual and organizational intervention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
Summary 2-Furyl vinyl ketone was polymerised using anionic, cationic and free-radical initiators. Yields and molecular weights varied with the type of activation. Whereas radical polymerisation gave a product possessing a regular vinylic structure, other kinds of units were detected in the polymers prepared with anionic and cationic catalysts.  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