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   3549013篇
  免费   285532篇
  国内免费   14723篇
耳鼻咽喉   49086篇
儿科学   108602篇
妇产科学   92338篇
基础医学   554242篇
口腔科学   97989篇
临床医学   314879篇
内科学   629577篇
皮肤病学   93858篇
神经病学   303764篇
特种医学   140952篇
外国民族医学   459篇
外科学   552471篇
综合类   107825篇
现状与发展   24篇
一般理论   2357篇
预防医学   289995篇
眼科学   81075篇
药学   247244篇
  23篇
中国医学   10425篇
肿瘤学   172083篇
  2021年   55393篇
  2020年   35367篇
  2019年   58488篇
  2018年   71639篇
  2017年   54697篇
  2016年   60536篇
  2015年   74577篇
  2014年   108918篇
  2013年   174415篇
  2012年   95808篇
  2011年   95545篇
  2010年   117436篇
  2009年   122101篇
  2008年   82820篇
  2007年   86892篇
  2006年   97409篇
  2005年   92339篇
  2004年   94572篇
  2003年   85366篇
  2002年   75510篇
  2001年   109560篇
  2000年   102613篇
  1999年   101580篇
  1998年   65465篇
  1997年   63303篇
  1996年   60775篇
  1995年   56214篇
  1994年   50424篇
  1993年   47116篇
  1992年   71860篇
  1991年   68145篇
  1990年   65104篇
  1989年   64461篇
  1988年   60321篇
  1987年   58944篇
  1986年   56414篇
  1985年   56080篇
  1984年   50570篇
  1983年   45839篇
  1982年   42378篇
  1981年   39826篇
  1980年   37672篇
  1979年   42996篇
  1978年   37398篇
  1977年   34296篇
  1976年   31056篇
  1975年   30712篇
  1974年   32424篇
  1973年   31111篇
  1972年   29529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.
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