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   4358890篇
  免费   339818篇
  国内免费   14726篇
耳鼻咽喉   60302篇
儿科学   139545篇
妇产科学   114359篇
基础医学   666910篇
口腔科学   118013篇
临床医学   397298篇
内科学   790713篇
皮肤病学   107730篇
神经病学   368397篇
特种医学   169514篇
外国民族医学   753篇
外科学   656282篇
综合类   121332篇
现状与发展   24篇
一般理论   2619篇
预防医学   360608篇
眼科学   100893篇
药学   307704篇
  26篇
中国医学   11933篇
肿瘤学   218479篇
  2021年   56163篇
  2020年   35816篇
  2019年   58809篇
  2018年   74380篇
  2017年   56996篇
  2016年   63110篇
  2015年   76074篇
  2014年   110273篇
  2013年   175807篇
  2012年   124359篇
  2011年   129085篇
  2010年   125905篇
  2009年   127622篇
  2008年   115270篇
  2007年   122561篇
  2006年   131350篇
  2005年   125432篇
  2004年   126723篇
  2003年   116951篇
  2002年   106158篇
  2001年   166981篇
  2000年   162080篇
  1999年   148717篇
  1998年   71686篇
  1997年   67618篇
  1996年   65638篇
  1995年   61057篇
  1994年   54985篇
  1993年   51027篇
  1992年   106657篇
  1991年   101430篇
  1990年   97285篇
  1989年   94863篇
  1988年   87189篇
  1987年   85347篇
  1986年   80235篇
  1985年   78392篇
  1984年   65422篇
  1983年   58212篇
  1982年   47195篇
  1981年   43871篇
  1980年   41086篇
  1979年   55132篇
  1978年   44774篇
  1977年   39994篇
  1976年   36858篇
  1975年   36822篇
  1974年   39634篇
  1973年   37769篇
  1972年   35384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