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   4198892篇
  免费   338495篇
  国内免费   14734篇
耳鼻咽喉   58512篇
儿科学   134937篇
妇产科学   111875篇
基础医学   642023篇
口腔科学   116743篇
临床医学   373982篇
内科学   759369篇
皮肤病学   103957篇
神经病学   353941篇
特种医学   167917篇
外国民族医学   790篇
外科学   646395篇
综合类   125681篇
现状与发展   23篇
一般理论   2527篇
预防医学   347290篇
眼科学   97860篇
药学   295002篇
  22篇
中国医学   11205篇
肿瘤学   202070篇
  2021年   55556篇
  2020年   35393篇
  2019年   58402篇
  2018年   72787篇
  2017年   55684篇
  2016年   61724篇
  2015年   75166篇
  2014年   109501篇
  2013年   174787篇
  2012年   111727篇
  2011年   114904篇
  2010年   122176篇
  2009年   125184篇
  2008年   102593篇
  2007年   108218篇
  2006年   117968篇
  2005年   113147篇
  2004年   115337篇
  2003年   105581篇
  2002年   95376篇
  2001年   146446篇
  2000年   141993篇
  1999年   133445篇
  1998年   69923篇
  1997年   66641篇
  1996年   64624篇
  1995年   60113篇
  1994年   54255篇
  1993年   50628篇
  1992年   99612篇
  1991年   95504篇
  1990年   91914篇
  1989年   89974篇
  1988年   83666篇
  1987年   82223篇
  1986年   78641篇
  1985年   77461篇
  1984年   65485篇
  1983年   58529篇
  1982年   47747篇
  1981年   44377篇
  1980年   41883篇
  1979年   57674篇
  1978年   46600篇
  1977年   41280篇
  1976年   38478篇
  1975年   38124篇
  1974年   42378篇
  1973年   40771篇
  1972年   37978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