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   4275646篇
  免费   350909篇
  国内免费   15280篇
耳鼻咽喉   60882篇
儿科学   132872篇
妇产科学   111709篇
基础医学   654568篇
口腔科学   118693篇
临床医学   387391篇
内科学   774794篇
皮肤病学   103191篇
神经病学   366126篇
特种医学   170493篇
外国民族医学   912篇
外科学   651544篇
综合类   126087篇
现状与发展   23篇
一般理论   2581篇
预防医学   361959篇
眼科学   100365篇
药学   301636篇
  24篇
中国医学   11352篇
肿瘤学   204633篇
  2021年   55641篇
  2020年   35454篇
  2019年   58555篇
  2018年   73125篇
  2017年   55841篇
  2016年   62151篇
  2015年   75458篇
  2014年   110177篇
  2013年   175483篇
  2012年   117179篇
  2011年   120171篇
  2010年   122722篇
  2009年   125933篇
  2008年   107406篇
  2007年   113897篇
  2006年   123445篇
  2005年   118595篇
  2004年   119564篇
  2003年   110297篇
  2002年   100923篇
  2001年   154289篇
  2000年   150450篇
  1999年   139524篇
  1998年   71253篇
  1997年   67736篇
  1996年   65623篇
  1995年   61486篇
  1994年   55564篇
  1993年   51595篇
  1992年   103565篇
  1991年   98956篇
  1990年   94053篇
  1989年   91691篇
  1988年   85311篇
  1987年   83769篇
  1986年   79473篇
  1985年   77903篇
  1984年   65941篇
  1983年   58853篇
  1982年   48129篇
  1981年   44873篇
  1980年   42164篇
  1979年   57825篇
  1978年   47039篇
  1977年   41593篇
  1976年   38656篇
  1975年   37850篇
  1974年   42419篇
  1973年   40548篇
  1972年   38019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