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   4257345篇
  免费   332918篇
  国内免费   13948篇
耳鼻咽喉   59123篇
儿科学   135828篇
妇产科学   111416篇
基础医学   655539篇
口腔科学   114395篇
临床医学   385977篇
内科学   768057篇
皮肤病学   106376篇
神经病学   353268篇
特种医学   164900篇
外国民族医学   505篇
外科学   653090篇
综合类   119869篇
现状与发展   24篇
一般理论   2604篇
预防医学   356084篇
眼科学   100031篇
药学   297157篇
  26篇
中国医学   11373篇
肿瘤学   208569篇
  2021年   55978篇
  2020年   35616篇
  2019年   58595篇
  2018年   74028篇
  2017年   56574篇
  2016年   62665篇
  2015年   75665篇
  2014年   110068篇
  2013年   175423篇
  2012年   123996篇
  2011年   129919篇
  2010年   126297篇
  2009年   127254篇
  2008年   116130篇
  2007年   124152篇
  2006年   132546篇
  2005年   127872篇
  2004年   128155篇
  2003年   118372篇
  2002年   107627篇
  2001年   149789篇
  2000年   144589篇
  1999年   134387篇
  1998年   70212篇
  1997年   66346篇
  1996年   64500篇
  1995年   59742篇
  1994年   53839篇
  1993年   50103篇
  1992年   96092篇
  1991年   92701篇
  1990年   89088篇
  1989年   86841篇
  1988年   80045篇
  1987年   78552篇
  1986年   73902篇
  1985年   73030篇
  1984年   61731篇
  1983年   55493篇
  1982年   46106篇
  1981年   43177篇
  1980年   40567篇
  1979年   53136篇
  1978年   44073篇
  1977年   38944篇
  1976年   36305篇
  1975年   36324篇
  1974年   39456篇
  1973年   37667篇
  1972年   35267篇
排序方式: 共有10000条查询结果,搜索用时 0 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