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   4277200篇
  免费   350878篇
  国内免费   15287篇
耳鼻咽喉   60920篇
儿科学   132920篇
妇产科学   111727篇
基础医学   654729篇
口腔科学   118751篇
临床医学   387470篇
内科学   775012篇
皮肤病学   103237篇
神经病学   366259篇
特种医学   170524篇
外国民族医学   912篇
外科学   651713篇
综合类   126106篇
现状与发展   23篇
一般理论   2580篇
预防医学   362222篇
眼科学   100406篇
药学   301750篇
  24篇
中国医学   11357篇
肿瘤学   204723篇
  2021年   55679篇
  2020年   35468篇
  2019年   58576篇
  2018年   73147篇
  2017年   55855篇
  2016年   62170篇
  2015年   75480篇
  2014年   110209篇
  2013年   175512篇
  2012年   117291篇
  2011年   120309篇
  2010年   122808篇
  2009年   125975篇
  2008年   107497篇
  2007年   113996篇
  2006年   123541篇
  2005年   118670篇
  2004年   119632篇
  2003年   110369篇
  2002年   100989篇
  2001年   154324篇
  2000年   150481篇
  1999年   139548篇
  1998年   71260篇
  1997年   67742篇
  1996年   65629篇
  1995年   61492篇
  1994年   55568篇
  1993年   51605篇
  1992年   103589篇
  1991年   98963篇
  1990年   94061篇
  1989年   91698篇
  1988年   85326篇
  1987年   83800篇
  1986年   79479篇
  1985年   77922篇
  1984年   65945篇
  1983年   58857篇
  1982年   48131篇
  1981年   44878篇
  1980年   42168篇
  1979年   57836篇
  1978年   47035篇
  1977年   41597篇
  1976年   38658篇
  1975年   37849篇
  1974年   42421篇
  1973年   40553篇
  1972年   38022篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
14.
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   
15.
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   
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