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   4093462篇
  免费   318512篇
  国内免费   15264篇
耳鼻咽喉   56860篇
儿科学   126352篇
妇产科学   107877篇
基础医学   626748篇
口腔科学   115055篇
临床医学   367417篇
内科学   730944篇
皮肤病学   105249篇
神经病学   342063篇
特种医学   161662篇
外国民族医学   612篇
外科学   626768篇
综合类   122023篇
现状与发展   24篇
一般理论   2435篇
预防医学   331588篇
眼科学   96009篇
药学   292364篇
  27篇
中国医学   11917篇
肿瘤学   203244篇
  2021年   55795篇
  2020年   35555篇
  2019年   58545篇
  2018年   72820篇
  2017年   55786篇
  2016年   61896篇
  2015年   75390篇
  2014年   109825篇
  2013年   175272篇
  2012年   108473篇
  2011年   110738篇
  2010年   121365篇
  2009年   124653篇
  2008年   97567篇
  2007年   103726篇
  2006年   113231篇
  2005年   107914篇
  2004年   109426篇
  2003年   100215篇
  2002年   90155篇
  2001年   146617篇
  2000年   141063篇
  1999年   132080篇
  1998年   69395篇
  1997年   66050篇
  1996年   63652篇
  1995年   59087篇
  1994年   53130篇
  1993年   49534篇
  1992年   95318篇
  1991年   90947篇
  1990年   87632篇
  1989年   86019篇
  1988年   79721篇
  1987年   77852篇
  1986年   74373篇
  1985年   72877篇
  1984年   62137篇
  1983年   55379篇
  1982年   46130篇
  1981年   42979篇
  1980年   40694篇
  1979年   53969篇
  1978年   44166篇
  1977年   40184篇
  1976年   36455篇
  1975年   37119篇
  1974年   40219篇
  1973年   38832篇
  1972年   36722篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
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   
15.
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   
16.
17.
18.
19.
20.

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   
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