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   17129篇
  免费   1021篇
  国内免费   83篇
耳鼻咽喉   145篇
儿科学   430篇
妇产科学   420篇
基础医学   2698篇
口腔科学   662篇
临床医学   1405篇
内科学   3800篇
皮肤病学   348篇
神经病学   2008篇
特种医学   461篇
外科学   1587篇
综合类   44篇
一般理论   6篇
预防医学   1038篇
眼科学   299篇
药学   1395篇
中国医学   57篇
肿瘤学   1430篇
  2024年   18篇
  2023年   173篇
  2022年   420篇
  2021年   613篇
  2020年   368篇
  2019年   489篇
  2018年   587篇
  2017年   461篇
  2016年   531篇
  2015年   661篇
  2014年   757篇
  2013年   957篇
  2012年   1490篇
  2011年   1606篇
  2010年   790篇
  2009年   753篇
  2008年   1185篇
  2007年   1128篇
  2006年   1036篇
  2005年   941篇
  2004年   854篇
  2003年   777篇
  2002年   663篇
  2001年   94篇
  2000年   70篇
  1999年   76篇
  1998年   108篇
  1997年   97篇
  1996年   60篇
  1995年   58篇
  1994年   43篇
  1993年   30篇
  1992年   23篇
  1991年   19篇
  1990年   18篇
  1989年   32篇
  1988年   22篇
  1987年   26篇
  1986年   20篇
  1985年   22篇
  1984年   20篇
  1983年   19篇
  1982年   17篇
  1981年   15篇
  1980年   8篇
  1979年   10篇
  1978年   8篇
  1976年   10篇
  1973年   9篇
  1969年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
2.
3.
4.
5.
6.

Background

The efficacy of dexamethasone in extending the duration of local anaesthetic block is uncertain. In a randomised controlled triple blind crossover study in volunteers, we tested the hypothesis that neither i.v. nor perineurally administered dexamethasone prolongs the sensory block achieved with ropivacaine.

Methods

Ultrasound-guided ulnar nerve blocks (ropivacaine 0.75% wt/vol, 3 ml, with saline 1 ml with or without dexamethasone 4 mg) were performed on three occasions in 24 male volunteers along with an i.v. injection of saline 1 ml with or without dexamethasone 4 mg. The combinations of saline and dexamethasone were as follows: control group, perineural and i.v. saline; perineural group, perineural dexamethasone and i.v. saline; i.v. group, perineural saline and i.v. dexamethasone. Sensory block was measured using a VAS in response to pinprick testing. The duration of sensory block was the primary outcome and time to onset of sensory block the secondary outcome.

Results

All 24 subjects completed the trial. The median [inter-quartile range (IQR)] duration of sensory block was 6.87 (5.85–7.62) h in the control group, 7.37 (5.78–7.93) h in the perineural group and 7.37 (6.10–7.97) h in the i.v. group (P=0.61). There was also no significant difference in block onset time between the three groups.

Conclusion

Dexamethasone 4 mg has no clinically relevant effect on the duration of sensory block provided by ropivacaine applied to the ulnar nerve.

Clinical trial registration

DRKS, 00014604; EudraCT, 2018-001221-98.  相似文献   
7.
8.
9.
BACKGROUND: In the central nervous system, several neuropeptides are believed to be involved in the pathophysiology of Alzheimer's disease (AD). Indeed, previous studies have documented that glucagon-like peptide 1 (GLP-1) possesses neurotropic properties and can reduce amyloid-beta peptide levels in the brain in vivo. Moreover, the concentrations of neuropeptide Y (NPY) seem to be altered in the cerebrospinal fluid of patients with AD and in subjects with major depression. Finally, among the modifications induced by aging, a dysregulation of the ghrelin-growth hormone (GH) system has been reported. METHODS: We investigated the plasma concentrations of these neuropeptides in 14 subjects with AD. Data obtained from these patients were compared with data from an age- and weight-matched healthy group. RESULTS: No significant differences were found between the two groups in relation to plasma levels of GLP-1, NPY, ghrelin and GH. Peripheral NPY concentrations were positively correlated with ghrelin levels in both groups, and with plasma GLP-1 concentration only in controls. CONCLUSION: On the basis of our results, peripheral levels of these neuropeptides seem not to serve as biochemical markers of AD.  相似文献   
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