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   3433466篇
  免费   282102篇
  国内免费   13319篇
耳鼻咽喉   46802篇
儿科学   109002篇
妇产科学   89239篇
基础医学   547084篇
口腔科学   92815篇
临床医学   312928篇
内科学   605863篇
皮肤病学   91129篇
神经病学   293476篇
特种医学   133862篇
外国民族医学   288篇
外科学   523815篇
综合类   102239篇
现状与发展   24篇
一般理论   2359篇
预防医学   294213篇
眼科学   77972篇
药学   234719篇
  27篇
中国医学   9325篇
肿瘤学   161706篇
  2021年   54855篇
  2020年   34960篇
  2019年   57864篇
  2018年   71114篇
  2017年   54224篇
  2016年   59627篇
  2015年   73794篇
  2014年   107862篇
  2013年   172953篇
  2012年   93531篇
  2011年   94008篇
  2010年   116702篇
  2009年   121061篇
  2008年   81233篇
  2007年   84657篇
  2006年   94579篇
  2005年   90309篇
  2004年   91913篇
  2003年   82654篇
  2002年   72503篇
  2001年   102452篇
  2000年   95116篇
  1999年   95185篇
  1998年   64512篇
  1997年   62574篇
  1996年   60731篇
  1995年   56166篇
  1994年   50425篇
  1993年   47102篇
  1992年   67524篇
  1991年   64780篇
  1990年   61415篇
  1989年   60585篇
  1988年   56419篇
  1987年   55184篇
  1986年   52616篇
  1985年   52207篇
  1984年   48135篇
  1983年   44307篇
  1982年   41696篇
  1981年   39417篇
  1980年   37150篇
  1979年   40649篇
  1978年   36250篇
  1977年   32830篇
  1976年   30116篇
  1975年   28998篇
  1974年   30482篇
  1973年   29595篇
  1972年   27850篇
排序方式: 共有10000条查询结果,搜索用时 0 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.

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   
19.
20.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  相似文献   
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