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   4324327篇
  免费   353072篇
  国内免费   15532篇
耳鼻咽喉   61429篇
儿科学   134009篇
妇产科学   112517篇
基础医学   660763篇
口腔科学   119893篇
临床医学   392246篇
内科学   784648篇
皮肤病学   103985篇
神经病学   370700篇
特种医学   172211篇
外国民族医学   912篇
外科学   659241篇
综合类   126533篇
现状与发展   23篇
一般理论   2729篇
预防医学   365398篇
眼科学   101383篇
药学   304809篇
  24篇
中国医学   11448篇
肿瘤学   208030篇
  2021年   56723篇
  2020年   36039篇
  2019年   59381篇
  2018年   74325篇
  2017年   56705篇
  2016年   63087篇
  2015年   76296篇
  2014年   111258篇
  2013年   176829篇
  2012年   121801篇
  2011年   125187篇
  2010年   124495篇
  2009年   127205篇
  2008年   111603篇
  2007年   118125篇
  2006年   127417篇
  2005年   122486篇
  2004年   123110篇
  2003年   113557篇
  2002年   103920篇
  2001年   154478篇
  2000年   150578篇
  1999年   139692篇
  1998年   71467篇
  1997年   67888篇
  1996年   65743篇
  1995年   61613篇
  1994年   55662篇
  1993年   51690篇
  1992年   103647篇
  1991年   99044篇
  1990年   94133篇
  1989年   91759篇
  1988年   85383篇
  1987年   83849篇
  1986年   79536篇
  1985年   77983篇
  1984年   66012篇
  1983年   58912篇
  1982年   48185篇
  1981年   44921篇
  1980年   42199篇
  1979年   57864篇
  1978年   47059篇
  1977年   41624篇
  1976年   38681篇
  1975年   37887篇
  1974年   42453篇
  1973年   40578篇
  1972年   38054篇
排序方式: 共有10000条查询结果,搜索用时 15 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