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   4112585篇
  免费   332522篇
  国内免费   14445篇
耳鼻咽喉   56792篇
儿科学   131202篇
妇产科学   107865篇
基础医学   634528篇
口腔科学   114968篇
临床医学   370401篇
内科学   737255篇
皮肤病学   103343篇
神经病学   343434篇
特种医学   163360篇
外国民族医学   555篇
外科学   631000篇
综合类   123234篇
现状与发展   23篇
一般理论   2476篇
预防医学   341357篇
眼科学   96303篇
药学   289266篇
  23篇
中国医学   11733篇
肿瘤学   200434篇
  2021年   55707篇
  2020年   35521篇
  2019年   58471篇
  2018年   72884篇
  2017年   55672篇
  2016年   61510篇
  2015年   75195篇
  2014年   109548篇
  2013年   174731篇
  2012年   108517篇
  2011年   111286篇
  2010年   121770篇
  2009年   124493篇
  2008年   98503篇
  2007年   103603篇
  2006年   113615篇
  2005年   108336篇
  2004年   110735篇
  2003年   100625篇
  2002年   90615篇
  2001年   144456篇
  2000年   139458篇
  1999年   131176篇
  1998年   69622篇
  1997年   66282篇
  1996年   64263篇
  1995年   59809篇
  1994年   53979篇
  1993年   50241篇
  1992年   97507篇
  1991年   94292篇
  1990年   90607篇
  1989年   89038篇
  1988年   82659篇
  1987年   80849篇
  1986年   77067篇
  1985年   76249篇
  1984年   64447篇
  1983年   57633篇
  1982年   47221篇
  1981年   44052篇
  1980年   41473篇
  1979年   56479篇
  1978年   45831篇
  1977年   40677篇
  1976年   38011篇
  1975年   37691篇
  1974年   41412篇
  1973年   39709篇
  1972年   36943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