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   4460931篇
  免费   353238篇
  国内免费   15426篇
耳鼻咽喉   62374篇
儿科学   139859篇
妇产科学   119563篇
基础医学   672619篇
口腔科学   127834篇
临床医学   397521篇
内科学   808548篇
皮肤病学   110043篇
神经病学   374270篇
特种医学   178416篇
外国民族医学   896篇
外科学   683224篇
综合类   133837篇
现状与发展   24篇
一般理论   2594篇
预防医学   363192篇
眼科学   104693篇
药学   318523篇
  23篇
中国医学   12240篇
肿瘤学   219302篇
  2021年   55787篇
  2019年   58586篇
  2018年   73326篇
  2017年   56143篇
  2016年   62354篇
  2015年   75646篇
  2014年   110104篇
  2013年   175494篇
  2012年   116603篇
  2011年   119912篇
  2010年   123313篇
  2009年   126122篇
  2008年   107704篇
  2007年   114554篇
  2006年   123951篇
  2005年   118870篇
  2004年   120970篇
  2003年   111421篇
  2002年   101452篇
  2001年   162318篇
  2000年   158100篇
  1999年   146699篇
  1998年   71420篇
  1997年   67680篇
  1996年   65485篇
  1995年   60916篇
  1994年   55145篇
  1993年   51353篇
  1992年   109888篇
  1991年   105539篇
  1990年   101693篇
  1989年   99855篇
  1988年   93041篇
  1987年   91206篇
  1986年   87170篇
  1985年   85560篇
  1984年   71040篇
  1983年   63054篇
  1982年   49605篇
  1981年   46031篇
  1980年   43430篇
  1979年   63661篇
  1978年   50575篇
  1977年   44841篇
  1976年   41347篇
  1975年   41901篇
  1974年   47096篇
  1973年   45335篇
  1972年   42594篇
  1971年   39591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.
19.

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   
20.
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