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   3142333篇
  免费   267926篇
  国内免费   13894篇
耳鼻咽喉   43618篇
儿科学   96515篇
妇产科学   81095篇
基础医学   505520篇
口腔科学   86265篇
临床医学   280422篇
内科学   544368篇
皮肤病学   84902篇
神经病学   272288篇
特种医学   125323篇
外国民族医学   196篇
外科学   493338篇
综合类   101366篇
现状与发展   24篇
一般理论   2193篇
预防医学   265736篇
眼科学   71359篇
药学   216434篇
  22篇
中国医学   9180篇
肿瘤学   143989篇
  2021年   54596篇
  2020年   34830篇
  2019年   57748篇
  2018年   70079篇
  2017年   53367篇
  2016年   58888篇
  2015年   73287篇
  2014年   107394篇
  2013年   172405篇
  2012年   83552篇
  2011年   81447篇
  2010年   113428篇
  2009年   118962篇
  2008年   68687篇
  2007年   70935篇
  2006年   82102篇
  2005年   77804篇
  2004年   80285篇
  2003年   71366篇
  2002年   61028篇
  2001年   84016篇
  2000年   76154篇
  1999年   80019篇
  1998年   63091篇
  1997年   61538篇
  1996年   59280篇
  1995年   54821篇
  1994年   49160篇
  1993年   45983篇
  1992年   57353篇
  1991年   54610篇
  1990年   51822篇
  1989年   51391篇
  1988年   48185篇
  1987年   47084篇
  1986年   44897篇
  1985年   45490篇
  1984年   43541篇
  1983年   40222篇
  1982年   40256篇
  1981年   38095篇
  1980年   36019篇
  1979年   36872篇
  1978年   33508篇
  1977年   30831篇
  1976年   28035篇
  1975年   26559篇
  1974年   27686篇
  1973年   26599篇
  1972年   25033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