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   4418719篇
  免费   356551篇
  国内免费   14613篇
耳鼻咽喉   62188篇
儿科学   143876篇
妇产科学   117996篇
基础医学   671507篇
口腔科学   122157篇
临床医学   396931篇
内科学   803222篇
皮肤病学   108020篇
神经病学   369958篇
特种医学   176534篇
外国民族医学   1087篇
外科学   674893篇
综合类   129749篇
现状与发展   23篇
一般理论   2621篇
预防医学   367915篇
眼科学   103781篇
药学   312689篇
  23篇
中国医学   11550篇
肿瘤学   213163篇
  2021年   56001篇
  2019年   58833篇
  2018年   73999篇
  2017年   56617篇
  2016年   62667篇
  2015年   75801篇
  2014年   110252篇
  2013年   175957篇
  2012年   118569篇
  2011年   122908篇
  2010年   124523篇
  2009年   126601篇
  2008年   110240篇
  2007年   116882篇
  2006年   126093篇
  2005年   121129篇
  2004年   123140篇
  2003年   113147篇
  2002年   103093篇
  2001年   160658篇
  2000年   157266篇
  1999年   145587篇
  1998年   71906篇
  1997年   67835篇
  1996年   65969篇
  1995年   61475篇
  1994年   55707篇
  1993年   51838篇
  1992年   109157篇
  1991年   105498篇
  1990年   101618篇
  1989年   98702篇
  1988年   91674篇
  1987年   90077篇
  1986年   85216篇
  1985年   84067篇
  1984年   69971篇
  1983年   62356篇
  1982年   49201篇
  1981年   45836篇
  1980年   43010篇
  1979年   61878篇
  1978年   49223篇
  1977年   43472篇
  1976年   40573篇
  1975年   40510篇
  1974年   44971篇
  1973年   43430篇
  1972年   40309篇
  1971年   37225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.

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   
19.
20.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  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