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   2790421篇
  免费   250538篇
  国内免费   30138篇
耳鼻咽喉   37336篇
儿科学   83267篇
妇产科学   63735篇
基础医学   441221篇
口腔科学   71502篇
临床医学   256492篇
内科学   442804篇
皮肤病学   78137篇
神经病学   228518篇
特种医学   109564篇
外国民族医学   26篇
外科学   419927篇
综合类   164524篇
现状与发展   93篇
一般理论   1999篇
预防医学   248339篇
眼科学   59012篇
药学   203456篇
  533篇
中国医学   39687篇
肿瘤学   120925篇
  2023年   16611篇
  2022年   32498篇
  2021年   66475篇
  2020年   45172篇
  2019年   62980篇
  2018年   74756篇
  2017年   60556篇
  2016年   63706篇
  2015年   84136篇
  2014年   121263篇
  2013年   190628篇
  2012年   93798篇
  2011年   89318篇
  2010年   134711篇
  2009年   139284篇
  2008年   72457篇
  2007年   69436篇
  2006年   79519篇
  2005年   70915篇
  2004年   68032篇
  2003年   57676篇
  2002年   46210篇
  2001年   57154篇
  2000年   47007篇
  1999年   54763篇
  1998年   59939篇
  1997年   59251篇
  1996年   56838篇
  1995年   52387篇
  1994年   46603篇
  1993年   43651篇
  1992年   34529篇
  1991年   32162篇
  1990年   29560篇
  1989年   30092篇
  1988年   28166篇
  1987年   27460篇
  1986年   26146篇
  1985年   27659篇
  1984年   30729篇
  1983年   29716篇
  1982年   35613篇
  1981年   34111篇
  1980年   32250篇
  1979年   22968篇
  1978年   24435篇
  1977年   23530篇
  1976年   21283篇
  1975年   18792篇
  1974年   17302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.

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