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   4224656篇
  免费   331500篇
  国内免费   13953篇
耳鼻咽喉   58731篇
儿科学   135003篇
妇产科学   110651篇
基础医学   651695篇
口腔科学   113662篇
临床医学   382498篇
内科学   761413篇
皮肤病学   106097篇
神经病学   350223篇
特种医学   163940篇
外国民族医学   506篇
外科学   648237篇
综合类   119351篇
现状与发展   24篇
一般理论   2568篇
预防医学   353788篇
眼科学   99073篇
药学   295043篇
  26篇
中国医学   11368篇
肿瘤学   206212篇
  2021年   56190篇
  2020年   35698篇
  2019年   58691篇
  2018年   74087篇
  2017年   56521篇
  2016年   62567篇
  2015年   75567篇
  2014年   110053篇
  2013年   175228篇
  2012年   121409篇
  2011年   127051篇
  2010年   125639篇
  2009年   126827篇
  2008年   112918篇
  2007年   120301篇
  2006年   129031篇
  2005年   124156篇
  2004年   124360篇
  2003年   114752篇
  2002年   103966篇
  2001年   149710篇
  2000年   144545篇
  1999年   134311篇
  1998年   70101篇
  1997年   66213篇
  1996年   64425篇
  1995年   59705篇
  1994年   53792篇
  1993年   50048篇
  1992年   96052篇
  1991年   92649篇
  1990年   89062篇
  1989年   86825篇
  1988年   80027篇
  1987年   78519篇
  1986年   73860篇
  1985年   72981篇
  1984年   61665篇
  1983年   55432篇
  1982年   46024篇
  1981年   43116篇
  1980年   40506篇
  1979年   53102篇
  1978年   44032篇
  1977年   38885篇
  1976年   36272篇
  1975年   36272篇
  1974年   39407篇
  1973年   37635篇
  1972年   35244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.

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