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   83459篇
  免费   41995篇
  国内免费   545篇
耳鼻咽喉   1530篇
儿科学   4362篇
妇产科学   679篇
基础医学   16045篇
口腔科学   5112篇
临床医学   13394篇
内科学   23795篇
皮肤病学   7512篇
神经病学   13464篇
特种医学   2354篇
外国民族医学   2篇
外科学   14242篇
综合类   1735篇
现状与发展   3篇
一般理论   23篇
预防医学   4854篇
眼科学   1366篇
药学   6403篇
  11篇
中国医学   1528篇
肿瘤学   7585篇
  2024年   44篇
  2023年   175篇
  2022年   384篇
  2021年   1663篇
  2020年   5322篇
  2019年   11022篇
  2018年   10321篇
  2017年   11666篇
  2016年   12277篇
  2015年   12203篇
  2014年   12179篇
  2013年   12704篇
  2012年   4675篇
  2011年   4606篇
  2010年   9378篇
  2009年   5653篇
  2008年   2446篇
  2007年   1247篇
  2006年   1253篇
  2005年   961篇
  2004年   894篇
  2003年   997篇
  2002年   1047篇
  2001年   995篇
  2000年   875篇
  1999年   359篇
  1998年   113篇
  1997年   96篇
  1996年   74篇
  1995年   49篇
  1994年   43篇
  1993年   27篇
  1992年   45篇
  1991年   39篇
  1990年   28篇
  1989年   30篇
  1988年   16篇
  1987年   21篇
  1986年   10篇
  1985年   9篇
  1984年   6篇
  1983年   15篇
  1982年   6篇
  1981年   8篇
  1980年   2篇
  1978年   5篇
  1977年   3篇
  1963年   1篇
  1962年   1篇
  1948年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
The first‐order kernel analysis in multifocal electroretinogram (mfERG) using low contrast stimulation is suggested as a way to detect the inner retinal responses in animal studies. In this case report, this protocol is applied to human patients with glaucoma to demonstrate the possibility of using mfERG as a tool to detect glaucomatous damage. Two patients with glaucoma were recruited and had mfERG measurements with the 103‐scaled hexagonal stimulus pattern at low (50 per cent) contrast. Their responses were analysed and compared with those from normal subjects with the mfERG measured under the same condition. In the normal subjects, there were obvious oscillatory components on the ascending and descending limbs of the first‐order kernel response to 50 per cent contrast. In the glaucomatous patients, the oscillatory component on the descending limb was obviously diminished. In addition, this component was significantly diminished in the quadrant with a glaucomatous visual field defect. This suggests that the low‐contrast stimulation condition in mERG measurement may provide a good way to detect glaucomatous damage and this may help in clinical diagnosis of glaucoma.  相似文献   
24.
Abstract: We have designed and synthesized a new series of azapeptides which act as potential inhibitors of cathepsin B and/or cathepsin K. Their structures are based upon the inhibitory sites of natural cysteine protease inhibitors, cystatins. For the synthesized azapeptides, the equilibrium constants for dissociation of inhibitor–enzyme complex, Ki, were determined. Comparison of these values indicated that all of the azainhibitors act much stronger toward cathepsin B. Z‐Arg‐Leu‐His‐Agly‐Ile‐Val‐OMe ( 7 ) proved to be approximately 500 times more potent for cathepsin B than for cathepsin K. To be able to explain the obtained experimental values we used the molecular dynamics procedures to analyze the interactions between cathepsin B and compound 7 . We also determined the structure of the most potent and selective cathepsin B azainhibitor by means of NMR studies and theoretical calculations. In this report, we describe SAR studies of azapeptide inhibitors indicating the influence of the conformational flexibility of the examined compounds on inhibition of cathepsins B and K.  相似文献   
25.
26.
1 The internal anal sphincter (IAS) has a spontaneous tone and is the main contributor to the maintenance of faecal continence. The spontaneous resting tone exhibited by the sphincter can be modified by neurotransmitters from the autonomic and enteric nervous systems. 2 In this review, the influence of the sympathetic and parasympathetic nervous systems on IAS tone are discussed and the putative roles of nitric oxide, carbon monoxide, vasoactive intestinal peptide and adenosine triphosphate in non‐adrenergic non‐cholinergic transmission are considered. 3 Faecal incontinence is a common condition that places a heavy financial burden on the health service and severely affects patients’ quality of life. Resting anal pressure is reduced in patients with faecal incontinence and agents that increase sphincter tone tend to relieve symptoms. The results of clinical studies of the use of phenylephrine to treat faecal incontinence are reviewed. 4 It is concluded that the IAS is a potential target for drug development for the treatment of faecal incontinence.  相似文献   
27.
28.
谭来勋  王芬  张弦 《疑难病杂志》2009,8(4):221-222
目的研究阿奇霉素对脑梗死后不明原因长期发热的疗效。方法用免疫荧光法测定不明原因长期发热脑梗死患者112例的血清抗肺炎衣原体抗体,患者随机分为2组并分别给予阿奇霉素和新青霉素加入生理盐水中静脉滴注10d,每日观察比较2组患者的病情。结果所有病例抗肺炎衣原体IgM抗体滴度均≥1∶16;阿奇霉素组显效率为92.86%,高于新青霉素组的44.64%,差异有统计学意义(P<0.01)。结论长期发热的脑梗死患者肺炎衣原体的感染率高,用阿奇霉素治疗效果好。  相似文献   
29.
30.
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