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   3938335篇
  免费   317150篇
  国内免费   14527篇
耳鼻咽喉   54576篇
儿科学   123363篇
妇产科学   104522篇
基础医学   610703篇
口腔科学   109891篇
临床医学   358435篇
内科学   701196篇
皮肤病学   99378篇
神经病学   332910篇
特种医学   154899篇
外国民族医学   442篇
外科学   600510篇
综合类   118779篇
现状与发展   24篇
一般理论   2520篇
预防医学   334421篇
眼科学   90708篇
药学   274476篇
  27篇
中国医学   10526篇
肿瘤学   187706篇
  2021年   55243篇
  2020年   35204篇
  2019年   58135篇
  2018年   72248篇
  2017年   55178篇
  2016年   60864篇
  2015年   74590篇
  2014年   108793篇
  2013年   173997篇
  2012年   107640篇
  2011年   110140篇
  2010年   120497篇
  2009年   123728篇
  2008年   96950篇
  2007年   102820篇
  2006年   111683篇
  2005年   107336篇
  2004年   108863篇
  2003年   99363篇
  2002年   88941篇
  2001年   126783篇
  2000年   120318篇
  1999年   115393篇
  1998年   67402篇
  1997年   64692篇
  1996年   62868篇
  1995年   58211篇
  1994年   52586篇
  1993年   49008篇
  1992年   85183篇
  1991年   82050篇
  1990年   78613篇
  1989年   77116篇
  1988年   72049篇
  1987年   70548篇
  1986年   67278篇
  1985年   66183篇
  1984年   58172篇
  1983年   52547篇
  1982年   45369篇
  1981年   42524篇
  1980年   40143篇
  1979年   51699篇
  1978年   43465篇
  1977年   38647篇
  1976年   35499篇
  1975年   35301篇
  1974年   38839篇
  1973年   37663篇
  1972年   35676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