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   4356126篇
  免费   339593篇
  国内免费   14723篇
耳鼻咽喉   60293篇
儿科学   139401篇
妇产科学   114198篇
基础医学   666488篇
口腔科学   117986篇
临床医学   396868篇
内科学   790196篇
皮肤病学   107721篇
神经病学   368199篇
特种医学   169434篇
外国民族医学   753篇
外科学   656005篇
综合类   121265篇
现状与发展   24篇
一般理论   2614篇
预防医学   360286篇
眼科学   100873篇
药学   307515篇
  26篇
中国医学   11933篇
肿瘤学   218364篇
  2021年   56142篇
  2020年   35800篇
  2019年   58782篇
  2018年   74350篇
  2017年   56966篇
  2016年   63081篇
  2015年   76048篇
  2014年   110244篇
  2013年   175770篇
  2012年   124158篇
  2011年   128881篇
  2010年   125833篇
  2009年   127567篇
  2008年   115091篇
  2007年   122359篇
  2006年   131177篇
  2005年   125269篇
  2004年   126581篇
  2003年   116787篇
  2002年   106036篇
  2001年   166930篇
  2000年   162012篇
  1999年   148658篇
  1998年   71655篇
  1997年   67603篇
  1996年   65621篇
  1995年   61042篇
  1994年   54966篇
  1993年   51009篇
  1992年   106612篇
  1991年   101378篇
  1990年   97240篇
  1989年   94813篇
  1988年   87142篇
  1987年   85307篇
  1986年   80192篇
  1985年   78350篇
  1984年   65395篇
  1983年   58195篇
  1982年   47187篇
  1981年   43856篇
  1980年   41072篇
  1979年   55104篇
  1978年   44753篇
  1977年   39979篇
  1976年   36838篇
  1975年   36804篇
  1974年   39608篇
  1973年   37750篇
  1972年   35359篇
排序方式: 共有10000条查询结果,搜索用时 15 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