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   4865239篇
  免费   369983篇
  国内免费   17048篇
耳鼻咽喉   67950篇
儿科学   156534篇
妇产科学   129808篇
基础医学   732993篇
口腔科学   134228篇
临床医学   449541篇
内科学   880026篇
皮肤病学   116923篇
神经病学   401025篇
特种医学   186669篇
外国民族医学   824篇
外科学   731309篇
综合类   138418篇
现状与发展   23篇
一般理论   2796篇
预防医学   413565篇
眼科学   114815篇
药学   342426篇
  30篇
中国医学   13314篇
肿瘤学   239053篇
  2021年   57049篇
  2019年   59495篇
  2018年   76456篇
  2017年   58493篇
  2016年   64663篇
  2015年   77164篇
  2014年   111778篇
  2013年   177626篇
  2012年   143050篇
  2011年   152361篇
  2010年   132675篇
  2009年   131467篇
  2008年   136970篇
  2007年   147043篇
  2006年   154328篇
  2005年   148934篇
  2004年   148249篇
  2003年   137704篇
  2002年   126466篇
  2001年   180170篇
  2000年   176713篇
  1999年   160185篇
  1998年   74141篇
  1997年   69195篇
  1996年   67269篇
  1995年   62619篇
  1994年   56724篇
  1993年   52645篇
  1992年   117717篇
  1991年   114426篇
  1990年   110238篇
  1989年   106852篇
  1988年   98762篇
  1987年   96932篇
  1986年   91810篇
  1985年   89868篇
  1984年   73571篇
  1983年   65258篇
  1982年   50227篇
  1981年   46749篇
  1980年   43821篇
  1979年   65109篇
  1978年   51715篇
  1977年   45002篇
  1976年   42509篇
  1975年   42965篇
  1974年   48264篇
  1973年   46480篇
  1972年   43605篇
  1971年   40723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