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   4883998篇
  免费   389110篇
  国内免费   16328篇
耳鼻咽喉   69351篇
儿科学   153740篇
妇产科学   130227篇
基础医学   732775篇
口腔科学   137056篇
临床医学   446160篇
内科学   890987篇
皮肤病学   114994篇
神经病学   413768篇
特种医学   192315篇
外国民族医学   1212篇
外科学   734595篇
综合类   143624篇
现状与发展   24篇
一般理论   2821篇
预防医学   413839篇
眼科学   116315篇
药学   345893篇
  24篇
中国医学   13101篇
肿瘤学   236615篇
  2021年   56512篇
  2019年   59186篇
  2018年   75304篇
  2017年   57708篇
  2016年   64298篇
  2015年   76868篇
  2014年   111792篇
  2013年   177285篇
  2012年   138700篇
  2011年   145300篇
  2010年   129123篇
  2009年   130328篇
  2008年   131413篇
  2007年   140678篇
  2006年   148700篇
  2005年   143596篇
  2004年   143789篇
  2003年   133689篇
  2002年   123491篇
  2001年   188121篇
  2000年   185662篇
  1999年   167413篇
  1998年   75679篇
  1997年   70837篇
  1996年   68733篇
  1995年   64462篇
  1994年   58383篇
  1993年   54115篇
  1992年   124138篇
  1991年   118692篇
  1990年   113170篇
  1989年   109942篇
  1988年   101980篇
  1987年   100290篇
  1986年   94755篇
  1985年   92481篇
  1984年   76378篇
  1983年   67461篇
  1982年   51774篇
  1981年   47919篇
  1980年   44985篇
  1979年   67790篇
  1978年   53460篇
  1977年   46649篇
  1976年   43513篇
  1975年   43260篇
  1974年   49398篇
  1973年   47534篇
  1972年   44634篇
  1971年   41032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.
20.

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   
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