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   3530498篇
  免费   295217篇
  国内免费   14165篇
耳鼻咽喉   47901篇
儿科学   112576篇
妇产科学   92344篇
基础医学   561185篇
口腔科学   93799篇
临床医学   317249篇
内科学   629445篇
皮肤病学   93291篇
神经病学   303818篇
特种医学   137854篇
外国民族医学   490篇
外科学   541126篇
综合类   107624篇
现状与发展   24篇
一般理论   2337篇
预防医学   297066篇
眼科学   80597篇
药学   241608篇
  22篇
中国医学   10471篇
肿瘤学   169053篇
  2021年   55169篇
  2020年   35134篇
  2019年   58151篇
  2018年   71608篇
  2017年   54712篇
  2016年   60482篇
  2015年   74344篇
  2014年   108573篇
  2013年   173667篇
  2012年   98892篇
  2011年   99384篇
  2010年   117841篇
  2009年   122232篇
  2008年   86192篇
  2007年   89809篇
  2006年   100277篇
  2005年   95556篇
  2004年   96985篇
  2003年   87432篇
  2002年   76899篇
  2001年   118115篇
  2000年   111570篇
  1999年   107517篇
  1998年   66639篇
  1997年   64233篇
  1996年   62074篇
  1995年   57522篇
  1994年   51464篇
  1993年   48035篇
  1992年   74192篇
  1991年   69865篇
  1990年   65607篇
  1989年   64402篇
  1988年   59367篇
  1987年   58076篇
  1986年   54614篇
  1985年   54412篇
  1984年   49485篇
  1983年   45057篇
  1982年   42165篇
  1981年   39543篇
  1980年   37232篇
  1979年   40221篇
  1978年   35566篇
  1977年   32274篇
  1976年   29612篇
  1975年   27937篇
  1974年   29005篇
  1973年   28026篇
  1972年   26228篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
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   
14.
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   
15.
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