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   4293291篇
  免费   341223篇
  国内免费   17123篇
耳鼻咽喉   58537篇
儿科学   138223篇
妇产科学   114309篇
基础医学   660465篇
口腔科学   116722篇
临床医学   396534篇
内科学   773522篇
皮肤病学   105691篇
神经病学   362797篇
特种医学   165660篇
外国民族医学   816篇
外科学   641192篇
综合类   127689篇
现状与发展   24篇
一般理论   2588篇
预防医学   367412篇
眼科学   99047篇
药学   298186篇
  27篇
中国医学   12472篇
肿瘤学   209724篇
  2021年   56356篇
  2020年   35851篇
  2019年   58987篇
  2018年   74475篇
  2017年   57007篇
  2016年   62985篇
  2015年   76140篇
  2014年   110686篇
  2013年   176436篇
  2012年   124581篇
  2011年   129755篇
  2010年   126204篇
  2009年   127629篇
  2008年   114796篇
  2007年   121647篇
  2006年   130416篇
  2005年   125154篇
  2004年   125433篇
  2003年   115099篇
  2002年   104089篇
  2001年   154914篇
  2000年   150408篇
  1999年   138774篇
  1998年   71197篇
  1997年   67582篇
  1996年   65395篇
  1995年   60897篇
  1994年   54913篇
  1993年   51043篇
  1992年   100158篇
  1991年   95967篇
  1990年   91742篇
  1989年   88867篇
  1988年   82295篇
  1987年   80380篇
  1986年   76092篇
  1985年   74736篇
  1984年   63629篇
  1983年   56809篇
  1982年   47098篇
  1981年   43854篇
  1980年   41163篇
  1979年   54486篇
  1978年   44742篇
  1977年   39539篇
  1976年   36996篇
  1975年   36003篇
  1974年   39604篇
  1973年   38427篇
  1972年   35843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.
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