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   11382篇
  免费   671篇
  国内免费   82篇
耳鼻咽喉   82篇
儿科学   286篇
妇产科学   179篇
基础医学   1131篇
口腔科学   154篇
临床医学   1217篇
内科学   2886篇
皮肤病学   177篇
神经病学   749篇
特种医学   297篇
外国民族医学   1篇
外科学   2099篇
综合类   290篇
现状与发展   1篇
一般理论   6篇
预防医学   641篇
眼科学   241篇
药学   959篇
中国医学   160篇
肿瘤学   579篇
  2024年   19篇
  2023年   186篇
  2022年   567篇
  2021年   741篇
  2020年   450篇
  2019年   573篇
  2018年   580篇
  2017年   356篇
  2016年   397篇
  2015年   437篇
  2014年   547篇
  2013年   649篇
  2012年   993篇
  2011年   947篇
  2010年   457篇
  2009年   435篇
  2008年   648篇
  2007年   634篇
  2006年   538篇
  2005年   535篇
  2004年   416篇
  2003年   407篇
  2002年   243篇
  2001年   59篇
  2000年   41篇
  1999年   35篇
  1998年   36篇
  1997年   17篇
  1996年   16篇
  1995年   12篇
  1994年   12篇
  1993年   15篇
  1992年   13篇
  1991年   9篇
  1990年   6篇
  1989年   8篇
  1988年   10篇
  1987年   5篇
  1985年   8篇
  1984年   8篇
  1983年   5篇
  1982年   7篇
  1981年   15篇
  1980年   7篇
  1979年   5篇
  1978年   6篇
  1977年   3篇
  1976年   4篇
  1975年   3篇
  1972年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
Kommerell’s diverticulum is a rare saccular aneurysmal dilation of the descending aorta. We report a case of a 3.5-year-old boy with the extremely rare combination of Kommerell’s diverticulum with a right descending aorta and proximal patent ductus arteriosus aneurysm forming an incomplete vascular ring. To our knowledge, this rare case has not been reported to date.  相似文献   
105.
Arsenic (As) is considered to be one of the top environmental contaminants of concern worldwide. In many regions in Pakistan, there are reports of increased levels of As in the environment, and this metalloid remains a major source of contamination of soil, water and fodder. This pathway of exposure has emerged as a new threat for both wildlife and the surrounding human communities because of the mobilization and accumulation of As via the food chain. The objective of this critical review is to synthesize historical information about As levels in the environmental resources of Pakistan to better characterize the risk to livestock and humans in the region. The South Punjab and Sindh are the dominant areas which are reported to contain the highest As contamination compared to other regions. This is a concern as millions of animals as well as the human population are facing significant health issues due to As. For example, some of the population of Sindh province are potentially faced with As levels ~10–50?μg/L in drinking water, which is well above safe drinking limits of 10?μg/L outlined by the World Health Organization. These collective data on As are anticipated to be a useful source of information for decisions by the environmental protection agency in Pakistan regarding the adoption of preventive measures against its adverse impacts and toxicity.  相似文献   
106.
107.
Context: Azadirachta indica A. Juss. (Meliaceaes) leaves have been used traditionally to treat swelling and rheumatism in Indian cultures.

Objective: To fractionate A. indica leaf extracts using bioactivity guided manner for identification of the active anti-inflammatory principles.

Materials and methods: Polarity-gradient sequential extracts (petroleum ether, chloroform, methanol, and water) of A. indica leaves were screened for their anti-inflammatory potential using the carrageenan-induced rat paw edema model (1?g/kg). The chloroform extract was sequentially fractionated to obtain n-hexane (F-1), n-hexane-chloroform (F-2), and chloroform (F-3) fractions and their inhibitory effect on rat paw edema was evaluated (500?mg/kg). Inhibitory effect of F-2 on granuloma formation, plasma interleukin (IL-1), and tumor necrosis factor (TNF-α) was assessed at the doses of 100, 200, and 400?mg/kg using the cotton pellet assay in rats. Three sub-fractions (SF-1, SF-2, and SF-3) were obtained upon chromatography of F-2, and their inhibitory effect on cyclooxygenase was assessed at 200?µg/mL concentration. The sub-fractions were subjected to gas chromatography–mass spectrometry (GC-MS).

Results: All the extracts showed significant anti-inflammatory effect; however, chloroform extract was the most effective against paw edema (53.25% inhibition). The three fractions of chloroform extract showed significant effect, while F-2 being the most potent (51.02%). F-2 demonstrated dose-dependent inhibition of granuloma and cytokines. Interestingly, all the sub-fractions of F-2 inhibited COX-1 and COX-2 with almost equal potential. GC-MS revealed that chemically the sub-fractions were totally different from each other.

Discussion and conclusion: Anti-inflammatory effect of A. indica is a result of cumulative and synergistic effects of diversified constituents with varying polarities that collectively exert the effect via suppression of cyclo-oxygenases and cytokines (IL-1 and TNF-α).  相似文献   
108.
109.
110.
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