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   4906484篇
  免费   370086篇
  国内免费   15681篇
耳鼻咽喉   69488篇
儿科学   154866篇
妇产科学   131431篇
基础医学   734536篇
口腔科学   137103篇
临床医学   443750篇
内科学   892253篇
皮肤病学   119490篇
神经病学   402679篇
特种医学   191567篇
外国民族医学   903篇
外科学   749080篇
综合类   138590篇
现状与发展   24篇
一般理论   2755篇
预防医学   401739篇
眼科学   116516篇
药学   348776篇
  27篇
中国医学   13257篇
肿瘤学   243421篇
  2021年   56416篇
  2019年   59018篇
  2018年   75343篇
  2017年   57748篇
  2016年   64114篇
  2015年   76615篇
  2014年   111169篇
  2013年   176580篇
  2012年   136857篇
  2011年   144760篇
  2010年   130038篇
  2009年   130094篇
  2008年   131142篇
  2007年   141618篇
  2006年   148996篇
  2005年   144136篇
  2004年   144153篇
  2003年   134446篇
  2002年   123852篇
  2001年   185449篇
  2000年   181637篇
  1999年   164566篇
  1998年   74065篇
  1997年   69037篇
  1996年   66995篇
  1995年   62215篇
  1994年   56367篇
  1993年   52322篇
  1992年   120874篇
  1991年   117011篇
  1990年   113173篇
  1989年   110443篇
  1988年   102243篇
  1987年   100420篇
  1986年   95178篇
  1985年   93118篇
  1984年   75734篇
  1983年   66909篇
  1982年   50842篇
  1981年   47102篇
  1980年   44374篇
  1979年   67665篇
  1978年   53502篇
  1977年   46978篇
  1976年   43565篇
  1975年   45391篇
  1974年   51012篇
  1973年   48889篇
  1972年   46252篇
  1971年   43097篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
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   
14.
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   
15.
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