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   4911067篇
  免费   384939篇
  国内免费   16649篇
耳鼻咽喉   70729篇
儿科学   151768篇
妇产科学   130811篇
基础医学   730740篇
口腔科学   140968篇
临床医学   444222篇
内科学   896438篇
皮肤病学   115914篇
神经病学   413749篇
特种医学   195114篇
外国民族医学   1269篇
外科学   745022篇
综合类   144056篇
现状与发展   24篇
一般理论   2775篇
预防医学   407321篇
眼科学   116988篇
药学   352194篇
  25篇
中国医学   13066篇
肿瘤学   239462篇
  2021年   56335篇
  2019年   59125篇
  2018年   74778篇
  2017年   57329篇
  2016年   63967篇
  2015年   76681篇
  2014年   111584篇
  2013年   177197篇
  2012年   133155篇
  2011年   138855篇
  2010年   127597篇
  2009年   129415篇
  2008年   126043篇
  2007年   135471篇
  2006年   143705篇
  2005年   138642篇
  2004年   139364篇
  2003年   129983篇
  2002年   120590篇
  2001年   186950篇
  2000年   184463篇
  1999年   167180篇
  1998年   74937篇
  1997年   70348篇
  1996年   67931篇
  1995年   63718篇
  1994年   57874篇
  1993年   53637篇
  1992年   125693篇
  1991年   120448篇
  1990年   115606篇
  1989年   112643篇
  1988年   104815篇
  1987年   102880篇
  1986年   98107篇
  1985年   95646篇
  1984年   78296篇
  1983年   68925篇
  1982年   52279篇
  1981年   48342篇
  1980年   45522篇
  1979年   70617篇
  1978年   55277篇
  1977年   48718篇
  1976年   45010篇
  1975年   45924篇
  1974年   52519篇
  1973年   50427篇
  1972年   47661篇
  1971年   44023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.
20.

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   
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