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   42423篇
  免费   2154篇
  国内免费   45篇
电工技术   320篇
综合类   21篇
化学工业   9288篇
金属工艺   754篇
机械仪表   909篇
建筑科学   1274篇
矿业工程   85篇
能源动力   1050篇
轻工业   7034篇
水利工程   411篇
石油天然气   158篇
武器工业   5篇
无线电   1719篇
一般工业技术   6905篇
冶金工业   8268篇
原子能技术   178篇
自动化技术   6243篇
  2024年   89篇
  2023年   383篇
  2022年   708篇
  2021年   1218篇
  2020年   919篇
  2019年   1086篇
  2018年   1616篇
  2017年   1551篇
  2016年   1669篇
  2015年   1277篇
  2014年   1609篇
  2013年   3262篇
  2012年   2496篇
  2011年   2554篇
  2010年   1959篇
  2009年   1847篇
  2008年   1751篇
  2007年   1586篇
  2006年   1139篇
  2005年   994篇
  2004年   914篇
  2003年   788篇
  2002年   763篇
  2001年   546篇
  2000年   496篇
  1999年   548篇
  1998年   2520篇
  1997年   1710篇
  1996年   1126篇
  1995年   692篇
  1994年   536篇
  1993年   604篇
  1992年   242篇
  1991年   243篇
  1990年   190篇
  1989年   186篇
  1988年   179篇
  1987年   161篇
  1986年   131篇
  1985年   160篇
  1984年   148篇
  1983年   107篇
  1982年   145篇
  1981年   148篇
  1980年   166篇
  1979年   83篇
  1978年   85篇
  1977年   289篇
  1976年   630篇
  1973年   65篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
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   
3.
Food Analytical Methods - The habanero pepper (Capsicum chinense Jacq.) is very aromatic and is the hottest pepper in the world. In this study, a headspace solid-phase microextraction/gas...  相似文献   
4.
5.
This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples. The experimental results revealed that the chitosan hydrogels are suitable for the formulation of sage essential oil. The monoterpene release can be effectively controlled by both chitosan and caffeine concentration in the hydrogels. Permeation experiment, based on a hydrogel with the optimized composition [3.5% (w/w) sage essential oil, 2.0% (w/w) caffeine, 2.5% (w/w) chitosan and 0.1% (w/w) Tween-80] in donor compartment, saline solution in acceptor compartment, and semi-permeable cellophane membrane, demonstrated the useful permeation selectivity. Here, (according to lipophilicity) an enhanced permeation of the bicyclic monoterpenes with antiflogistic and antiseptic properties (eucalyptol, camphor and borneol) and, at the same time, suppressed permeation of toxic thujone (not exceeding its permitted applicable concentration) was observed. These properties highlight the pharmaceutical importance of the developed chitosan hydrogel formulating sage essential oil in the dermal applications.  相似文献   
6.
7.
8.
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