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   4275267篇
  免费   350868篇
  国内免费   15280篇
耳鼻咽喉   60882篇
儿科学   132863篇
妇产科学   111699篇
基础医学   654492篇
口腔科学   118685篇
临床医学   387310篇
内科学   774689篇
皮肤病学   103188篇
神经病学   366107篇
特种医学   170483篇
外国民族医学   912篇
外科学   651464篇
综合类   126073篇
现状与发展   23篇
一般理论   2578篇
预防医学   361939篇
眼科学   100365篇
药学   301611篇
  24篇
中国医学   11352篇
肿瘤学   204676篇
  2021年   55640篇
  2020年   35453篇
  2019年   58554篇
  2018年   73122篇
  2017年   55842篇
  2016年   62147篇
  2015年   75455篇
  2014年   110174篇
  2013年   175476篇
  2012年   117165篇
  2011年   120164篇
  2010年   122721篇
  2009年   125922篇
  2008年   107395篇
  2007年   113886篇
  2006年   123432篇
  2005年   118582篇
  2004年   119535篇
  2003年   110279篇
  2002年   100905篇
  2001年   154277篇
  2000年   150434篇
  1999年   139508篇
  1998年   71249篇
  1997年   67732篇
  1996年   65619篇
  1995年   61481篇
  1994年   55560篇
  1993年   51595篇
  1992年   103554篇
  1991年   98938篇
  1990年   94041篇
  1989年   91677篇
  1988年   85297篇
  1987年   83764篇
  1986年   79457篇
  1985年   77896篇
  1984年   65932篇
  1983年   58842篇
  1982年   48127篇
  1981年   44869篇
  1980年   42162篇
  1979年   57821篇
  1978年   47027篇
  1977年   41589篇
  1976年   38650篇
  1975年   37843篇
  1974年   42413篇
  1973年   40546篇
  1972年   38014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