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   3454816篇
  免费   296240篇
  国内免费   13903篇
耳鼻咽喉   47413篇
儿科学   108996篇
妇产科学   87692篇
基础医学   550357篇
口腔科学   93236篇
临床医学   312595篇
内科学   613021篇
皮肤病学   89378篇
神经病学   297694篇
特种医学   138340篇
外国民族医学   299篇
外科学   534893篇
综合类   106009篇
现状与发展   24篇
一般理论   2265篇
预防医学   293653篇
眼科学   78761篇
药学   237817篇
  24篇
中国医学   9565篇
肿瘤学   162927篇
  2021年   55151篇
  2020年   35105篇
  2019年   58105篇
  2018年   71350篇
  2017年   54318篇
  2016年   60024篇
  2015年   74164篇
  2014年   108465篇
  2013年   173499篇
  2012年   92291篇
  2011年   92234篇
  2010年   116688篇
  2009年   121113篇
  2008年   79292篇
  2007年   82516篇
  2006年   93192篇
  2005年   88721篇
  2004年   90791篇
  2003年   81735篇
  2002年   70964篇
  2001年   111141篇
  2000年   104748篇
  1999年   102335篇
  1998年   66231篇
  1997年   63860篇
  1996年   62036篇
  1995年   57780篇
  1994年   51793篇
  1993年   48395篇
  1992年   73587篇
  1991年   70294篇
  1990年   66630篇
  1989年   65192篇
  1988年   60455篇
  1987年   59116篇
  1986年   55922篇
  1985年   56023篇
  1984年   50478篇
  1983年   45786篇
  1982年   42565篇
  1981年   39997篇
  1980年   37701篇
  1979年   41799篇
  1978年   36574篇
  1977年   33150篇
  1976年   30464篇
  1975年   29052篇
  1974年   30281篇
  1973年   29047篇
  1972年   27048篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
15.
Vestibular function laboratories utilize a multitude of diagnostic instruments to evaluate a dizzy patient. Caloric irrigators, oculomotor stimuli, and rotational chairs produce a stimulus whose accuracy is required for the patient response to be accurate. Careful attention to everything from cleanliness of equipment to threshold adjustments determine on a daily basis if patient data are going to be correct and useful. Instrumentation specifications that change with time such as speed and temperature must periodically be checked using calibrated instruments.  相似文献   
16.
17.
18.
19.

Background

Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to median sternotomy (MS) for multiple valvular disease (MVD). This systematic review and meta-analysis aims to compare operative and peri-operative outcomes of MIS vs MS in MVD.

Methods

PubMed, Ovid, and Embase were searched from inception until August 2019 for randomized and observational studies comparing MIS and MS in patients with MVD. Clinical outcomes of intra- and postoperative times, reoperation for bleeding and surgical site infection were evaluated.

Results

Five observational studies comparing 340 MIS vs 414 MS patients were eligible for qualitative and quantitative review. The quality of evidence assessed using the Newcastle-Ottawa scale was good for all included studies. Meta-analysis demonstrated increased cardiopulmonary bypass time for MIS patients (weighted mean difference [WMD], 0.487; 95% confidence interval [CI], 0.365-0.608; P < .0001). Similarly, aortic cross-clamp time was longer in patients undergoing MIS (WMD, 0.632; 95% CI, 0.509-0.755; P < .0001). No differences were found in operative mortality, reoperation for bleeding, surgical site infection, or hospital stay.

Conclusions

MIS for MVD have similar short-term outcomes compared to MS. This adds value to the use of minimally invasive methods for multivalvular surgery, despite conferring longer operative times. However, the paucity in literature and learning curve associated with MIS warrants further evidence, ideally randomized control trials, to support these findings.
  相似文献   
20.
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