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   4444006篇
  免费   343824篇
  国内免费   15011篇
耳鼻咽喉   61345篇
儿科学   141412篇
妇产科学   115731篇
基础医学   678107篇
口腔科学   119976篇
临床医学   405687篇
内科学   807557篇
皮肤病学   109583篇
神经病学   376174篇
特种医学   172912篇
外国民族医学   762篇
外科学   668941篇
综合类   122473篇
现状与发展   24篇
一般理论   2687篇
预防医学   366808篇
眼科学   102881篇
药学   313883篇
  26篇
中国医学   12108篇
肿瘤学   223764篇
  2021年   57270篇
  2020年   36508篇
  2019年   59801篇
  2018年   75633篇
  2017年   57960篇
  2016年   64322篇
  2015年   77143篇
  2014年   111716篇
  2013年   177682篇
  2012年   130841篇
  2011年   136643篇
  2010年   128605篇
  2009年   129875篇
  2008年   121990篇
  2007年   129957篇
  2006年   138453篇
  2005年   132478篇
  2004年   133257篇
  2003年   123118篇
  2002年   112314篇
  2001年   167865篇
  2000年   162863篇
  1999年   149463篇
  1998年   72226篇
  1997年   68051篇
  1996年   65961篇
  1995年   61356篇
  1994年   55251篇
  1993年   51267篇
  1992年   107117篇
  1991年   101842篇
  1990年   97659篇
  1989年   95208篇
  1988年   87520篇
  1987年   85667篇
  1986年   80564篇
  1985年   78674篇
  1984年   65638篇
  1983年   58409篇
  1982年   47335篇
  1981年   44003篇
  1980年   41217篇
  1979年   55359篇
  1978年   44949篇
  1977年   40137篇
  1976年   37020篇
  1975年   36962篇
  1974年   39825篇
  1973年   37938篇
  1972年   35546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