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   4111533篇
  免费   322131篇
  国内免费   17818篇
耳鼻咽喉   56345篇
儿科学   126167篇
妇产科学   106799篇
基础医学   633472篇
口腔科学   114106篇
临床医学   377332篇
内科学   734198篇
皮肤病学   101270篇
神经病学   344603篇
特种医学   159022篇
外国民族医学   466篇
外科学   625951篇
综合类   122445篇
现状与发展   32篇
一般理论   2429篇
预防医学   343488篇
眼科学   94575篇
药学   289930篇
  46篇
中国医学   13596篇
肿瘤学   205210篇
  2021年   56834篇
  2020年   36333篇
  2019年   59208篇
  2018年   73965篇
  2017年   56654篇
  2016年   62326篇
  2015年   76319篇
  2014年   110961篇
  2013年   176701篇
  2012年   114346篇
  2011年   117645篇
  2010年   124341篇
  2009年   126355篇
  2008年   103779篇
  2007年   108685篇
  2006年   118370篇
  2005年   112844篇
  2004年   113533篇
  2003年   103471篇
  2002年   93013篇
  2001年   147826篇
  2000年   142885篇
  1999年   133403篇
  1998年   69731篇
  1997年   66454篇
  1996年   64136篇
  1995年   59603篇
  1994年   53650篇
  1993年   49917篇
  1992年   96768篇
  1991年   92870篇
  1990年   88740篇
  1989年   86616篇
  1988年   80115篇
  1987年   78179篇
  1986年   74097篇
  1985年   73216篇
  1984年   62032篇
  1983年   55490篇
  1982年   46079篇
  1981年   42977篇
  1980年   40284篇
  1979年   52594篇
  1978年   43100篇
  1977年   38712篇
  1976年   35632篇
  1975年   34887篇
  1974年   37984篇
  1973年   36339篇
  1972年   34142篇
排序方式: 共有10000条查询结果,搜索用时 0 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