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   3159224篇
  免费   262182篇
  国内免费   13793篇
耳鼻咽喉   43686篇
儿科学   99851篇
妇产科学   81438篇
基础医学   507353篇
口腔科学   84246篇
临床医学   278345篇
内科学   556050篇
皮肤病学   85726篇
神经病学   272423篇
特种医学   125314篇
外国民族医学   361篇
外科学   496787篇
综合类   96717篇
现状与发展   23篇
一般理论   2167篇
预防医学   263803篇
眼科学   71144篇
药学   214277篇
  22篇
中国医学   9195篇
肿瘤学   146271篇
  2021年   54630篇
  2020年   34854篇
  2019年   57808篇
  2018年   70213篇
  2017年   53546篇
  2016年   59071篇
  2015年   73418篇
  2014年   107399篇
  2013年   172462篇
  2012年   83990篇
  2011年   82969篇
  2010年   114164篇
  2009年   119463篇
  2008年   70869篇
  2007年   72865篇
  2006年   83939篇
  2005年   79920篇
  2004年   81860篇
  2003年   73255篇
  2002年   63348篇
  2001年   89200篇
  2000年   81793篇
  1999年   84928篇
  1998年   63418篇
  1997年   61771篇
  1996年   59481篇
  1995年   54925篇
  1994年   49124篇
  1993年   45915篇
  1992年   58540篇
  1991年   55222篇
  1990年   52403篇
  1989年   51793篇
  1988年   48337篇
  1987年   47254篇
  1986年   45299篇
  1985年   45490篇
  1984年   43087篇
  1983年   39915篇
  1982年   39839篇
  1981年   37589篇
  1980年   35551篇
  1979年   35090篇
  1978年   32153篇
  1977年   29699篇
  1976年   27278篇
  1975年   25791篇
  1974年   26283篇
  1973年   25129篇
  1972年   23657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