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   4289905篇
  免费   351641篇
  国内免费   15312篇
耳鼻咽喉   61016篇
儿科学   133390篇
妇产科学   112102篇
基础医学   656493篇
口腔科学   119074篇
临床医学   389129篇
内科学   777457篇
皮肤病学   103471篇
神经病学   367565篇
特种医学   170856篇
外国民族医学   912篇
外科学   652801篇
综合类   126253篇
现状与发展   23篇
一般理论   2599篇
预防医学   363387篇
眼科学   100633篇
药学   302574篇
  24篇
中国医学   11389篇
肿瘤学   205710篇
  2021年   55816篇
  2020年   35601篇
  2019年   58740篇
  2018年   73340篇
  2017年   56040篇
  2016年   62369篇
  2015年   75714篇
  2014年   110434篇
  2013年   175880篇
  2012年   118281篇
  2011年   121347篇
  2010年   123178篇
  2009年   126307篇
  2008年   108486篇
  2007年   115067篇
  2006年   124595篇
  2005年   119659篇
  2004年   120625篇
  2003年   111333篇
  2002年   101902篇
  2001年   154419篇
  2000年   150570篇
  1999年   139659篇
  1998年   71389篇
  1997年   67826篇
  1996年   65698篇
  1995年   61546篇
  1994年   55615篇
  1993年   51674篇
  1992年   103672篇
  1991年   99024篇
  1990年   94124篇
  1989年   91765篇
  1988年   85379篇
  1987年   83855篇
  1986年   79528篇
  1985年   77988篇
  1984年   65998篇
  1983年   58893篇
  1982年   48163篇
  1981年   44907篇
  1980年   42200篇
  1979年   57868篇
  1978年   47074篇
  1977年   41628篇
  1976年   38675篇
  1975年   37870篇
  1974年   42452篇
  1973年   40573篇
  1972年   38051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