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   4291898篇
  免费   351565篇
  国内免费   15322篇
耳鼻咽喉   61084篇
儿科学   133355篇
妇产科学   111966篇
基础医学   656482篇
口腔科学   118895篇
临床医学   389176篇
内科学   777754篇
皮肤病学   103397篇
神经病学   367532篇
特种医学   171141篇
外国民族医学   912篇
外科学   653943篇
综合类   126318篇
现状与发展   23篇
一般理论   2609篇
预防医学   363601篇
眼科学   100652篇
药学   302934篇
  24篇
中国医学   11374篇
肿瘤学   205613篇
  2021年   55877篇
  2020年   35593篇
  2019年   58759篇
  2018年   73425篇
  2017年   56057篇
  2016年   62389篇
  2015年   75665篇
  2014年   110452篇
  2013年   175835篇
  2012年   118781篇
  2011年   121944篇
  2010年   123243篇
  2009年   126313篇
  2008年   108869篇
  2007年   115527篇
  2006年   124851篇
  2005年   119970篇
  2004年   120908篇
  2003年   111514篇
  2002年   102092篇
  2001年   154347篇
  2000年   150519篇
  1999年   139578篇
  1998年   71327篇
  1997年   67769篇
  1996年   65650篇
  1995年   61517篇
  1994年   55589篇
  1993年   51627篇
  1992年   103591篇
  1991年   98975篇
  1990年   94078篇
  1989年   91725篇
  1988年   85331篇
  1987年   83781篇
  1986年   79480篇
  1985年   77919篇
  1984年   65953篇
  1983年   58856篇
  1982年   48137篇
  1981年   44884篇
  1980年   42172篇
  1979年   57832篇
  1978年   47033篇
  1977年   41603篇
  1976年   38665篇
  1975年   37853篇
  1974年   42424篇
  1973年   40558篇
  1972年   38023篇
排序方式: 共有10000条查询结果,搜索用时 15 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