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   3981篇
  免费   212篇
  国内免费   24篇
耳鼻咽喉   58篇
儿科学   71篇
妇产科学   44篇
基础医学   526篇
口腔科学   465篇
临床医学   275篇
内科学   790篇
皮肤病学   115篇
神经病学   329篇
特种医学   72篇
外科学   494篇
综合类   17篇
预防医学   459篇
眼科学   42篇
药学   201篇
中国医学   36篇
肿瘤学   223篇
  2023年   38篇
  2022年   72篇
  2021年   150篇
  2020年   84篇
  2019年   114篇
  2018年   160篇
  2017年   92篇
  2016年   102篇
  2015年   135篇
  2014年   194篇
  2013年   240篇
  2012年   320篇
  2011年   376篇
  2010年   174篇
  2009年   151篇
  2008年   233篇
  2007年   208篇
  2006年   224篇
  2005年   170篇
  2004年   197篇
  2003年   127篇
  2002年   101篇
  2001年   71篇
  2000年   66篇
  1999年   59篇
  1998年   31篇
  1997年   16篇
  1996年   15篇
  1995年   20篇
  1994年   10篇
  1993年   8篇
  1992年   32篇
  1991年   32篇
  1990年   24篇
  1989年   28篇
  1988年   18篇
  1987年   11篇
  1986年   10篇
  1985年   12篇
  1984年   8篇
  1983年   12篇
  1982年   4篇
  1981年   4篇
  1973年   6篇
  1972年   6篇
  1971年   4篇
  1970年   7篇
  1969年   6篇
  1968年   4篇
  1965年   3篇
排序方式: 共有4217条查询结果,搜索用时 15 毫秒
1.
2.
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   
3.
Newly graduated nurses often finish orientation and then believe they still need more support and mentoring than is available. Retention rates suffer as they think it must be better elsewhere. This article reports a community hospital's implementation of an education-based preceptor program. A convenience sample of 40 new graduates participated in the study. Qualitative and quantitative findings indicate a high level of satisfaction (mean visual analogue scale score 93.7), 29% increase in retention, and 9.5% decrease in vacancy.  相似文献   
4.
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   
5.
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   
6.
7.
8.
9.
A comparative chronic inhalation exposure study was performed to investigate the potential health effects of gasoline and ethanol engine exhaust fumes. Test atmospheres of gasoline and ethanol exhaust were given to Wistar rats and Balb C mice housed in inhalation chambers for a period of 5 weeks. Gas concentration and physical parameters were continually monitored during the exposure period. Several biological parameters were assessed after the exposure including pulmonary function, mutagenicity, and hematological, biochemical, and morphological examinations. The results demonstrated that the chronic toxicity of the gasoline-fueled engine is significantly higher than that of the ethanol engine.  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