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   3518774篇
  免费   286664篇
  国内免费   15992篇
耳鼻咽喉   47479篇
儿科学   112056篇
妇产科学   91423篇
基础医学   559022篇
口腔科学   94288篇
临床医学   324375篇
内科学   618717篇
皮肤病学   91121篇
神经病学   302297篇
特种医学   135892篇
外国民族医学   392篇
外科学   531785篇
综合类   106513篇
现状与发展   23篇
一般理论   2322篇
预防医学   304369篇
眼科学   79747篇
药学   241413篇
  27篇
中国医学   10488篇
肿瘤学   167681篇
  2021年   55606篇
  2020年   35421篇
  2019年   58474篇
  2018年   72321篇
  2017年   55120篇
  2016年   60675篇
  2015年   74654篇
  2014年   109006篇
  2013年   174633篇
  2012年   100873篇
  2011年   102206篇
  2010年   119469篇
  2009年   122701篇
  2008年   87621篇
  2007年   91121篇
  2006年   101367篇
  2005年   96453篇
  2004年   97559篇
  2003年   87754篇
  2002年   77331篇
  2001年   107450篇
  2000年   100770篇
  1999年   99498篇
  1998年   65717篇
  1997年   63564篇
  1996年   61242篇
  1995年   56861篇
  1994年   51008篇
  1993年   47586篇
  1992年   70767篇
  1991年   67879篇
  1990年   64428篇
  1989年   62813篇
  1988年   58401篇
  1987年   57001篇
  1986年   54411篇
  1985年   54278篇
  1984年   49249篇
  1983年   44874篇
  1982年   42015篇
  1981年   39591篇
  1980年   37224篇
  1979年   40762篇
  1978年   35916篇
  1977年   32465篇
  1976年   30305篇
  1975年   28545篇
  1974年   30018篇
  1973年   28914篇
  1972年   27059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