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   3061025篇
  免费   246357篇
  国内免费   13326篇
耳鼻咽喉   41346篇
儿科学   95728篇
妇产科学   75675篇
基础医学   498363篇
口腔科学   78688篇
临床医学   279244篇
内科学   525634篇
皮肤病学   85090篇
神经病学   261949篇
特种医学   120648篇
外国民族医学   92篇
外科学   480961篇
综合类   89896篇
现状与发展   24篇
一般理论   2211篇
预防医学   258704篇
眼科学   69763篇
药学   205802篇
  22篇
中国医学   8881篇
肿瘤学   141987篇
  2022年   23537篇
  2021年   56050篇
  2020年   35646篇
  2019年   58956篇
  2018年   72298篇
  2017年   54930篇
  2016年   60472篇
  2015年   74717篇
  2014年   109240篇
  2013年   175007篇
  2012年   90957篇
  2011年   91562篇
  2010年   117830篇
  2009年   121651篇
  2008年   76512篇
  2007年   79679篇
  2006年   89572篇
  2005年   85252篇
  2004年   86526篇
  2003年   76957篇
  2002年   66675篇
  2001年   73052篇
  2000年   64423篇
  1999年   70604篇
  1998年   62509篇
  1997年   60840篇
  1996年   58398篇
  1995年   53843篇
  1994年   47867篇
  1993年   44894篇
  1992年   47060篇
  1991年   46311篇
  1990年   43872篇
  1989年   44065篇
  1988年   40881篇
  1987年   40034篇
  1986年   37911篇
  1985年   38905篇
  1984年   38546篇
  1983年   36178篇
  1982年   38044篇
  1981年   36245篇
  1980年   34324篇
  1979年   30716篇
  1978年   29496篇
  1977年   27323篇
  1976年   25499篇
  1975年   24497篇
  1974年   23858篇
  1973年   22826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