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   3765091篇
  免费   313364篇
  国内免费   13882篇
耳鼻咽喉   51485篇
儿科学   119836篇
妇产科学   98281篇
基础医学   587491篇
口腔科学   103791篇
临床医学   337480篇
内科学   671871篇
皮肤病学   95902篇
神经病学   322489篇
特种医学   150447篇
外国民族医学   500篇
外科学   580709篇
综合类   114423篇
现状与发展   23篇
一般理论   2473篇
预防医学   314766篇
眼科学   87069篇
药学   263483篇
  22篇
中国医学   10195篇
肿瘤学   179601篇
  2021年   55540篇
  2020年   35392篇
  2019年   58443篇
  2018年   72194篇
  2017年   55033篇
  2016年   60919篇
  2015年   74811篇
  2014年   109238篇
  2013年   174642篇
  2012年   102445篇
  2011年   103446篇
  2010年   119590篇
  2009年   123380篇
  2008年   90553篇
  2007年   94509篇
  2006年   105083篇
  2005年   99917篇
  2004年   102519篇
  2003年   92501篇
  2002年   82162篇
  2001年   121109篇
  2000年   115350篇
  1999年   111933篇
  1998年   67248篇
  1997年   64740篇
  1996年   62697篇
  1995年   58309篇
  1994年   52448篇
  1993年   48974篇
  1992年   83049篇
  1991年   79507篇
  1990年   76032篇
  1989年   74713篇
  1988年   69516篇
  1987年   68234篇
  1986年   64990篇
  1985年   64894篇
  1984年   56641篇
  1983年   51334篇
  1982年   44801篇
  1981年   41951篇
  1980年   39549篇
  1979年   48994篇
  1978年   40993篇
  1977年   36800篇
  1976年   34097篇
  1975年   32851篇
  1974年   35556篇
  1973年   34226篇
  1972年   31717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