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   4296440篇
  免费   352280篇
  国内免费   15303篇
耳鼻咽喉   61128篇
儿科学   133486篇
妇产科学   112338篇
基础医学   657199篇
口腔科学   119292篇
临床医学   390251篇
内科学   777944篇
皮肤病学   103461篇
神经病学   367703篇
特种医学   171368篇
外国民族医学   913篇
外科学   653964篇
综合类   126476篇
现状与发展   23篇
一般理论   2593篇
预防医学   364681篇
眼科学   100906篇
药学   303222篇
  25篇
中国医学   11381篇
肿瘤学   205669篇
  2021年   55777篇
  2020年   35523篇
  2019年   58669篇
  2018年   73322篇
  2017年   56001篇
  2016年   62310篇
  2015年   75579篇
  2014年   110324篇
  2013年   175697篇
  2012年   118369篇
  2011年   121485篇
  2010年   123084篇
  2009年   126145篇
  2008年   108543篇
  2007年   115188篇
  2006年   124647篇
  2005年   119846篇
  2004年   120677篇
  2003年   111361篇
  2002年   101995篇
  2001年   154922篇
  2000年   151114篇
  1999年   140055篇
  1998年   71425篇
  1997年   67867篇
  1996年   65748篇
  1995年   61610篇
  1994年   55669篇
  1993年   51701篇
  1992年   104038篇
  1991年   99411篇
  1990年   94517篇
  1989年   92122篇
  1988年   85704篇
  1987年   84182篇
  1986年   79830篇
  1985年   78293篇
  1984年   66227篇
  1983年   59071篇
  1982年   48265篇
  1981年   44984篇
  1980年   42279篇
  1979年   58113篇
  1978年   47241篇
  1977年   41761篇
  1976年   38817篇
  1975年   38018篇
  1974年   42626篇
  1973年   40762篇
  1972年   38214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