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   930434篇
  免费   53130篇
  国内免费   1407篇
耳鼻咽喉   10771篇
儿科学   31149篇
妇产科学   21653篇
基础医学   135374篇
口腔科学   22337篇
临床医学   80394篇
内科学   174924篇
皮肤病学   17661篇
神经病学   70266篇
特种医学   36311篇
外国民族医学   76篇
外科学   141367篇
综合类   17720篇
现状与发展   2篇
一般理论   188篇
预防医学   73620篇
眼科学   19718篇
药学   65968篇
  3篇
中国医学   3046篇
肿瘤学   62423篇
  2021年   6249篇
  2019年   6223篇
  2018年   31710篇
  2017年   25194篇
  2016年   29264篇
  2015年   9387篇
  2014年   12203篇
  2013年   17754篇
  2012年   29737篇
  2011年   45525篇
  2010年   33200篇
  2009年   25308篇
  2008年   43339篇
  2007年   48323篇
  2006年   24198篇
  2005年   24802篇
  2004年   25866篇
  2003年   26645篇
  2002年   23620篇
  2001年   37198篇
  2000年   38105篇
  1999年   31083篇
  1998年   8476篇
  1997年   7286篇
  1996年   7356篇
  1995年   7034篇
  1994年   6501篇
  1993年   5936篇
  1992年   23423篇
  1991年   23446篇
  1990年   22797篇
  1989年   22478篇
  1988年   20387篇
  1987年   19817篇
  1986年   18842篇
  1985年   17647篇
  1984年   13015篇
  1983年   11023篇
  1982年   6182篇
  1979年   11774篇
  1978年   8317篇
  1977年   6950篇
  1976年   6753篇
  1975年   7366篇
  1974年   8643篇
  1973年   8247篇
  1972年   7729篇
  1971年   7200篇
  1970年   6989篇
  1969年   6401篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
41.
42.
43.
44.
45.
46.
In the 6th Basic Plan for Long-Term Electricity Supply and Demand (6th BPE) for Korea, for the first time, the environmental costs of air pollution caused by oxides of sulfur (SOx), oxides of nitrogen (NOx), and particulate matters (PM) from power plants were estimated and included. However, several deficiencies in evaluating the environmental costs were found. In this study, (1) the validity of the environmental costs used in the 6th BPE was assessed, (2) a systematic approach was suggested and used to improve the environmental costs estimation, and (3) the sensitivity of the cost of generating electricity to the environmental costs by fuel type with the proposed approach was discussed. We found that the applied environmental costs used in the 6th BPE did not fully include the demographic characteristics of Korea. By applying more realistic parameter values, it was found that the newly estimated environmental cost was about 23 times higher than the cost estimated in the original 6th BPE for coal-fired power plants and about 1.5 times higher for liquefied natural gas (LNG)-fired power plants, suggesting that LNG-fired power plants are more economical if using more realistic environmental costs. Thus, it is critical to check the validity of parameter values when calculating environmental costs.  相似文献   
47.
48.
49.
Context Withania somnifera (L.) Dunal is traditionally used for treating various ailments, but lacks scientific evaluation.

Objective This study evaluates Withania somnifera (WS) for its effect on platelet activity and inflammatory enzymes.

Materials and methods Aqueous and ethanolic (1:1) leaf extracts were subjected to in vitro indirect haemolytic activity using Naja naja venom, human platelet aggregation was quantified for lipid peroxidation using arachidonic acid (AA) as agonist and 5-lipoxygenase (5-LOX) levels were determined using standard spectrometric assays. Further, molecular docking was performed by the ligand fit method using molegro software package (Molegro ApS, Aarhus, Denmark).

Results The study found that aqueous and ethanol extracts have very negligible effect (15%) with an IC50 value of 13.8?mg/mL on PLA2 from Naja naja venom. Further, extracts of WS also had very little effect (18%) with an IC50 value of 16.6?mg/mL on malondialdehyde (MDA) formation. However, a 65% inhibition of 5-LOX with an IC50 value of 0.92?mg/mL was observed in 1:1 ethanol extracts. The same was evident from SAR model with the active ingredient withaferin A binding predominantly on Phe 77, Tyr 98, Arg 99, Asp 164, Leu 168, Ser 382, Arg 395, Tyr 396 and Tyr 614 with an atomic contact energy value of??128.96 compared to standard phenidone (?103.61). Thus, the current study validates the application of WS for inflammatory diseases.

Conclusion This study reveals the inhibitory potential of W. somnifera on inflammatory enzymes and platelet aggregation. Thus, WS can serve as a newer, safer and affordable medicine for inflammatory diseases.  相似文献   
50.
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