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   3860972篇
  免费   307381篇
  国内免费   14519篇
耳鼻咽喉   53341篇
儿科学   119020篇
妇产科学   99124篇
基础医学   601335篇
口腔科学   107411篇
临床医学   347330篇
内科学   687140篇
皮肤病学   98989篇
神经病学   324671篇
特种医学   151604篇
外国民族医学   394篇
外科学   600168篇
综合类   113347篇
现状与发展   23篇
一般理论   2406篇
预防医学   316223篇
眼科学   89581篇
药学   270130篇
  25篇
中国医学   10826篇
肿瘤学   189784篇
  2021年   55282篇
  2020年   35266篇
  2019年   58278篇
  2018年   72158篇
  2017年   55192篇
  2016年   60891篇
  2015年   74872篇
  2014年   109176篇
  2013年   174483篇
  2012年   101431篇
  2011年   103250篇
  2010年   119636篇
  2009年   123111篇
  2008年   90772篇
  2007年   94907篇
  2006年   105234篇
  2005年   100214篇
  2004年   102139篇
  2003年   92868篇
  2002年   82642篇
  2001年   136923篇
  2000年   131289篇
  1999年   124226篇
  1998年   68496篇
  1997年   65281篇
  1996年   63140篇
  1995年   58569篇
  1994年   52658篇
  1993年   48928篇
  1992年   89845篇
  1991年   85898篇
  1990年   82156篇
  1989年   80888篇
  1988年   74307篇
  1987年   73146篇
  1986年   68781篇
  1985年   68344篇
  1984年   58601篇
  1983年   52620篇
  1982年   44960篇
  1981年   42096篇
  1980年   39440篇
  1979年   49345篇
  1978年   41280篇
  1977年   37384篇
  1976年   34003篇
  1975年   33408篇
  1974年   35807篇
  1973年   34245篇
  1972年   32063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