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   3746847篇
  免费   312757篇
  国内免费   13832篇
耳鼻咽喉   51190篇
儿科学   119386篇
妇产科学   97958篇
基础医学   585684篇
口腔科学   103607篇
临床医学   335518篇
内科学   668858篇
皮肤病学   95731篇
神经病学   320431篇
特种医学   149567篇
外国民族医学   498篇
外科学   577094篇
综合类   114287篇
现状与发展   23篇
一般理论   2418篇
预防医学   313268篇
眼科学   86751篇
药学   262509篇
  22篇
中国医学   10176篇
肿瘤学   178460篇
  2021年   55369篇
  2020年   35283篇
  2019年   58262篇
  2018年   71875篇
  2017年   54879篇
  2016年   60675篇
  2015年   74592篇
  2014年   108985篇
  2013年   174250篇
  2012年   100696篇
  2011年   101434篇
  2010年   118829篇
  2009年   122838篇
  2008年   88931篇
  2007年   92750篇
  2006年   103544篇
  2005年   98438篇
  2004年   100868篇
  2003年   91114篇
  2002年   80939篇
  2001年   120989篇
  2000年   115264篇
  1999年   111855篇
  1998年   67179篇
  1997年   64703篇
  1996年   62684篇
  1995年   58260篇
  1994年   52431篇
  1993年   48953篇
  1992年   82997篇
  1991年   79463篇
  1990年   75996篇
  1989年   74647篇
  1988年   69485篇
  1987年   68178篇
  1986年   64977篇
  1985年   64844篇
  1984年   56623篇
  1983年   51327篇
  1982年   44794篇
  1981年   41951篇
  1980年   39547篇
  1979年   48989篇
  1978年   40992篇
  1977年   36817篇
  1976年   34104篇
  1975年   32854篇
  1974年   35555篇
  1973年   34209篇
  1972年   31705篇
排序方式: 共有10000条查询结果,搜索用时 9 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.

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   
19.
20.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  相似文献   
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