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   44310篇
  免费   2422篇
  国内免费   47篇
电工技术   354篇
综合类   26篇
化学工业   9448篇
金属工艺   839篇
机械仪表   895篇
建筑科学   1340篇
矿业工程   91篇
能源动力   1010篇
轻工业   7227篇
水利工程   426篇
石油天然气   163篇
武器工业   5篇
无线电   1781篇
一般工业技术   7313篇
冶金工业   9320篇
原子能技术   198篇
自动化技术   6343篇
  2024年   94篇
  2023年   381篇
  2022年   726篇
  2021年   1224篇
  2020年   910篇
  2019年   1039篇
  2018年   1771篇
  2017年   1712篇
  2016年   1792篇
  2015年   1329篇
  2014年   1640篇
  2013年   3257篇
  2012年   2575篇
  2011年   2559篇
  2010年   1995篇
  2009年   1867篇
  2008年   1756篇
  2007年   1646篇
  2006年   1161篇
  2005年   1014篇
  2004年   899篇
  2003年   795篇
  2002年   769篇
  2001年   583篇
  2000年   552篇
  1999年   583篇
  1998年   2917篇
  1997年   1952篇
  1996年   1264篇
  1995年   766篇
  1994年   594篇
  1993年   663篇
  1992年   248篇
  1991年   260篇
  1990年   193篇
  1989年   195篇
  1988年   196篇
  1987年   172篇
  1986年   155篇
  1985年   178篇
  1984年   150篇
  1983年   123篇
  1982年   158篇
  1981年   181篇
  1980年   182篇
  1979年   89篇
  1978年   96篇
  1977年   307篇
  1976年   665篇
  1973年   79篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
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   
2.
3.
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   
4.
5.
6.
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   
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