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   5186篇
  免费   278篇
  国内免费   30篇
耳鼻咽喉   60篇
儿科学   107篇
妇产科学   72篇
基础医学   720篇
口腔科学   467篇
临床医学   336篇
内科学   1092篇
皮肤病学   138篇
神经病学   528篇
特种医学   100篇
外科学   705篇
综合类   24篇
预防医学   526篇
眼科学   59篇
药学   250篇
中国医学   44篇
肿瘤学   266篇
  2023年   47篇
  2022年   94篇
  2021年   182篇
  2020年   109篇
  2019年   138篇
  2018年   192篇
  2017年   114篇
  2016年   126篇
  2015年   161篇
  2014年   220篇
  2013年   288篇
  2012年   401篇
  2011年   474篇
  2010年   223篇
  2009年   194篇
  2008年   312篇
  2007年   294篇
  2006年   319篇
  2005年   242篇
  2004年   289篇
  2003年   197篇
  2002年   159篇
  2001年   83篇
  2000年   71篇
  1999年   65篇
  1998年   47篇
  1997年   24篇
  1996年   19篇
  1995年   32篇
  1994年   13篇
  1993年   19篇
  1992年   36篇
  1991年   39篇
  1990年   24篇
  1989年   30篇
  1988年   20篇
  1987年   15篇
  1986年   14篇
  1985年   15篇
  1984年   14篇
  1983年   19篇
  1982年   8篇
  1981年   10篇
  1980年   6篇
  1978年   7篇
  1976年   6篇
  1973年   6篇
  1972年   7篇
  1970年   8篇
  1969年   6篇
排序方式: 共有5494条查询结果,搜索用时 312 毫秒
1.
2.
3.
4.
INTRODUCTION: In patients (pts) with atrial fibrillation (AF) of more than 48 hours' duration, electrical cardioversion (ECV) should only be performed after 3 weeks of effective anticoagulation. Transesophageal echocardiography (TEE) allows earlier ECV; however, despite exclusion of thrombi in the atrium and left atrial appendage (LAA), cases of thromboembolism related to ECV have been documented in AF. To define a low-risk group for cardioversion without previous anticoagulation, pts were selected for immediate ECV if no thrombi or dynamic spontaneous echo contrast (auto-contrast) were found after TEE and if LAA velocity was more than 0.25 m/sec. METHODS AND RESULTS: We performed TEE in 31 consecutive pts referred for ECV for AF of more than 48 hours' duration and without previous anticoagulation. After TEE the pts eligible for immediate ECV began anticoagulation with low molecular weight heparin (enoxaparin), subcutaneously in therapeutic doses, together with warfarin immediately before cardioversion. Enoxaparin was continued until an INR of over 2 was reached. Based on the TEE findings, the pts were divided in 2 groups: immediate ECV, group A, 20 pts with a mean age of 62 +/- 13 years, 6 female; and conventional therapy with warfarin before ECV, group B, 11 pts, mean age of 67 +/- 10 years (p < 0.05), 2 female. None of the pts in either group had mitral stenosis or previous episodes of thromboembolism. The mean transverse diameter of the left atrium in the 31 pts was 47 +/- 4.5 mm, without statistically significant differences between the 2 groups. Of the 11 pts in group B, 3 had a thrombus in the LAA, 6 dynamic spontaneous echo contrast and the remainder LAA velocities of less than 0.25 m/sec. ECV was achieved in all the pts, with no complications. Oral anticoagulation was maintained for at least a month. At one month, sinus rhythm was maintained in 75% of group A and 45% of group B (p < 0.01). CONCLUSION: In pts with AF of more than 48 hours' duration and no previous history of thromboembolism, the use of our exclusion criteria during TEE enabled stratification of a low-risk population for immediate ECV, which was accomplished effectively and safely in 2/3 of the pts. This strategy is associated with early symptomatic improvement, and may contribute to maintenance of sinus rhythm after one month, which was significantly better than in the pts who had prolonged therapy with warfarin before ECV, despite the differences found in age and left ventricular function.  相似文献   
5.
We report a case of mammaplasty followed by a marked convergence of the nipple-areolar complex and describe the surgical repair by means of an inferior dermal-fat curved flap. The curve of the inferior pedicle permits one to raise the nipple to its normal position with ease and exceptional viability, even if a breast reduction procedure is associated.  相似文献   
6.
Loxosceles gaucho spider venom causes a typical dermonecrotic lesion in bitten patients and rarely causes lethal systemic effects. Gel filtration on Sephadex G 100 of L. gaucho spider venom resulted in three fractions: fraction A, containing the higher mol. wt components (approximately 35,000); fraction B, containing lower mol. wt components (approximately 15,000); and fraction C, containing very low mol. wt components (probably small peptides). The dermonecrotic and lethal activities were detected exclusively in fraction A. The venom and fraction A produced large dermonecrotic lesions in rabbits with necrosis spreading by gravity to the skin of the lateral body wall. Analysis by SDS-PAGE showed that the proteins contained in fraction A are approximately 35,000 and 33,000 mol. wt. Immunoblotting analysis showed that the proteins responsible for the dermonecrotic and lethal activity are very immunogenic and the first to be detected by antibodies during the course of immunization.  相似文献   
7.
8.
9.
10.
A polymerase chain reaction (PCR) method for the detection of the glmM gene, selected as Helicobacter pylori target sequence, was improved. While performing pathogenicity island cagA gene detection to discriminate pathogenic strains in atherosclerotic carotid samples, several cagA-positive but glmM-negative samples were found. Polymorphisms present in the region amplified in the nested PCR reaction could explain this result; primers were therefore designed to perform a seminested reaction; this modification optimized sensitivity while maintaining specificity. A real-time PCR for Helicobacter DNA detection was also setup. The combination of all 4 PCR reactions detected 83% of H. pylori DNA-positive samples in atherosclerotic carotid tissue, 64% of which were cagA gene positive.  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