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   3447925篇
  免费   296049篇
  国内免费   13878篇
耳鼻咽喉   47321篇
儿科学   108907篇
妇产科学   87652篇
基础医学   549337篇
口腔科学   93060篇
临床医学   312212篇
内科学   611333篇
皮肤病学   89294篇
神经病学   297232篇
特种医学   137962篇
外国民族医学   302篇
外科学   533632篇
综合类   105985篇
现状与发展   24篇
一般理论   2264篇
预防医学   293328篇
眼科学   78677篇
药学   237431篇
  24篇
中国医学   9547篇
肿瘤学   162328篇
  2021年   55076篇
  2020年   35049篇
  2019年   58050篇
  2018年   71273篇
  2017年   54240篇
  2016年   59925篇
  2015年   74065篇
  2014年   108367篇
  2013年   173378篇
  2012年   91992篇
  2011年   91860篇
  2010年   116467篇
  2009年   120955篇
  2008年   78976篇
  2007年   82131篇
  2006年   92769篇
  2005年   88297篇
  2004年   90308篇
  2003年   81238篇
  2002年   70368篇
  2001年   110978篇
  2000年   104582篇
  1999年   102160篇
  1998年   66158篇
  1997年   63778篇
  1996年   61980篇
  1995年   57730篇
  1994年   51746篇
  1993年   48352篇
  1992年   73473篇
  1991年   70189篇
  1990年   66517篇
  1989年   65086篇
  1988年   60358篇
  1987年   59021篇
  1986年   55847篇
  1985年   55956篇
  1984年   50407篇
  1983年   45752篇
  1982年   42539篇
  1981年   39964篇
  1980年   37666篇
  1979年   41758篇
  1978年   36556篇
  1977年   33109篇
  1976年   30454篇
  1975年   29027篇
  1974年   30264篇
  1973年   29032篇
  1972年   27029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.

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   
20.
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