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   3500029篇
  免费   283436篇
  国内免费   14702篇
耳鼻咽喉   48613篇
儿科学   107280篇
妇产科学   91737篇
基础医学   548227篇
口腔科学   97230篇
临床医学   309265篇
内科学   620488篇
皮肤病学   93284篇
神经病学   298540篇
特种医学   139294篇
外国民族医学   458篇
外科学   545420篇
综合类   107330篇
现状与发展   25篇
一般理论   2269篇
预防医学   285556篇
眼科学   80025篇
药学   243910篇
  23篇
中国医学   10437篇
肿瘤学   168756篇
  2021年   55432篇
  2020年   35296篇
  2019年   58345篇
  2018年   71346篇
  2017年   54396篇
  2016年   60176篇
  2015年   74253篇
  2014年   108595篇
  2013年   173851篇
  2012年   91236篇
  2011年   90517篇
  2010年   116088篇
  2009年   121109篇
  2008年   77891篇
  2007年   81439篇
  2006年   92189篇
  2005年   87481篇
  2004年   89628篇
  2003年   80930篇
  2002年   71191篇
  2001年   109339篇
  2000年   102438篇
  1999年   101371篇
  1998年   65260篇
  1997年   63152篇
  1996年   60665篇
  1995年   56116篇
  1994年   50345篇
  1993年   47030篇
  1992年   71738篇
  1991年   68046篇
  1990年   65024篇
  1989年   64358篇
  1988年   60243篇
  1987年   58862篇
  1986年   56342篇
  1985年   55977篇
  1984年   50491篇
  1983年   45778篇
  1982年   42327篇
  1981年   39785篇
  1980年   37629篇
  1979年   42943篇
  1978年   37361篇
  1977年   34270篇
  1976年   31040篇
  1975年   30690篇
  1974年   32406篇
  1973年   31081篇
  1972年   29505篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
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   
14.
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   
15.
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