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   56700篇
  免费   3303篇
  国内免费   183篇
电工技术   821篇
综合类   79篇
化学工业   11971篇
金属工艺   2303篇
机械仪表   3522篇
建筑科学   1316篇
矿业工程   28篇
能源动力   2429篇
轻工业   4516篇
水利工程   300篇
石油天然气   91篇
武器工业   2篇
无线电   9254篇
一般工业技术   12096篇
冶金工业   4667篇
原子能技术   725篇
自动化技术   6066篇
  2024年   28篇
  2023年   584篇
  2022年   761篇
  2021年   1646篇
  2020年   1203篇
  2019年   1305篇
  2018年   1646篇
  2017年   1587篇
  2016年   2000篇
  2015年   1495篇
  2014年   2393篇
  2013年   3531篇
  2012年   3649篇
  2011年   4390篇
  2010年   3199篇
  2009年   3355篇
  2008年   3230篇
  2007年   2545篇
  2006年   2349篇
  2005年   1993篇
  2004年   1825篇
  2003年   1740篇
  2002年   1543篇
  2001年   1305篇
  2000年   1166篇
  1999年   1118篇
  1998年   1860篇
  1997年   1212篇
  1996年   978篇
  1995年   683篇
  1994年   574篇
  1993年   483篇
  1992年   346篇
  1991年   329篇
  1990年   314篇
  1989年   296篇
  1988年   244篇
  1987年   211篇
  1986年   168篇
  1985年   152篇
  1984年   116篇
  1983年   95篇
  1982年   46篇
  1981年   60篇
  1980年   50篇
  1979年   43篇
  1978年   44篇
  1977年   57篇
  1976年   86篇
  1975年   31篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
Evaluation of kinetic distribution and behaviors of nanoparticles in vivo provides crucial clues into their roles in living organisms. Extracellular vesicles are evolutionary conserved nanoparticles, known to play important biological functions in intercellular, inter‐species, and inter‐kingdom communication. In this study, the first kinetic analysis of the biodistribution of outer membrane vesicles (OMVs)—bacterial extracellular vesicles—with immune‐modulatory functions is performed. OMVs, injected intraperitoneally, spread to the whole mouse body and accumulate in the liver, lung, spleen, and kidney within 3 h of administration. As an early systemic inflammation response, increased levels of TNF‐α and IL‐6 are observed in serum and bronchoalveolar lavage fluid. In addition, the number of leukocytes and platelets in the blood is decreased. OMVs and cytokine concentrations, as well as body temperature are gradually decreased 6 h after OMV injection, in concomitance with the formation of eye exudates, and of an increase in ICAM‐1 levels in the lung. Following OMV elimination, most of the inflammatory signs are reverted, 12 h post‐injection. However, leukocytes in bronchoalveolar lavage fluid are increased as a late reaction. Taken together, these results suggest that OMVs are effective mediators of long distance communication in vivo.  相似文献   
33.
34.
35.
36.
Machine Learning - We consider the problem of learning a binary classifier from only positive and unlabeled observations (called PU learning). Recent studies in PU learning have shown superior...  相似文献   
37.
Microsystem Technologies - A color-laser printing system consisting of a tandem laser scanning unit uses four laser diodes and a single polygonal mirror (PM) to expose light onto four...  相似文献   
38.
39.
40.
While exercise training (ET) is an efficient strategy to manage obesity, it is recommended with a dietary plan to maximize the antiobesity functions owing to a compensational increase in energy intake. Capsiate is a notable bioactive compound for managing obesity owing to its capacity to increase energy expenditure. We aimed to examine whether the antiobesity effects of ET can be further enhanced by capsiate intake (CI) and determine its effects on resting energy expenditure and metabolic molecules. Mice were randomly divided into four groups (n = 8 per group) and fed high-fat diet. Mild-intensity treadmill ET was conducted five times/week; capsiate (10 mg/kg) was orally administered daily. After 8 weeks, resting metabolic rate and metabolic molecules were analyzed. ET with CI additively reduced the abdominal fat rate by 18% and solely upregulated beta-3-adrenoceptors in adipose tissue (p = 0.013) but did not affect the metabolic molecules in skeletal muscles. Surprisingly, CI without ET significantly increased the abdominal fat rate (p = 0.001) and reduced energy expenditure by 9%. Therefore, capsiate could be a candidate compound for maximizing the antiobesity effects of ET by upregulating beta-3-adrenoceptors in adipose tissue, but CI without ET may not be beneficial in managing obesity.  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