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   4958453篇
  免费   383829篇
  国内免费   15688篇
耳鼻咽喉   69273篇
儿科学   158686篇
妇产科学   130531篇
基础医学   742916篇
口腔科学   137625篇
临床医学   456339篇
内科学   905103篇
皮肤病学   117449篇
神经病学   415332篇
特种医学   193917篇
外国民族医学   968篇
外科学   742704篇
综合类   139304篇
现状与发展   24篇
一般理论   2850篇
预防医学   414770篇
眼科学   116275篇
药学   353195篇
  26篇
中国医学   13006篇
肿瘤学   247677篇
  2021年   57037篇
  2019年   59456篇
  2018年   76348篇
  2017年   58581篇
  2016年   64929篇
  2015年   77439篇
  2014年   111916篇
  2013年   177729篇
  2012年   141638篇
  2011年   149713篇
  2010年   131484篇
  2009年   131348篇
  2008年   134891篇
  2007年   144973篇
  2006年   152489篇
  2005年   146754篇
  2004年   147546篇
  2003年   137206篇
  2002年   125920篇
  2001年   197325篇
  2000年   194258篇
  1999年   174352篇
  1998年   75981篇
  1997年   70667篇
  1996年   68823篇
  1995年   64405篇
  1994年   58242篇
  1993年   54077篇
  1992年   128606篇
  1991年   123421篇
  1990年   118849篇
  1989年   115398篇
  1988年   106304篇
  1987年   104345篇
  1986年   98444篇
  1985年   95854篇
  1984年   77830篇
  1983年   68488篇
  1982年   51672篇
  1981年   47750篇
  1980年   44758篇
  1979年   67705篇
  1978年   53069篇
  1977年   46631篇
  1976年   43262篇
  1975年   44082篇
  1974年   49010篇
  1973年   46943篇
  1972年   43942篇
  1971年   40628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