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   3998049篇
  免费   320617篇
  国内免费   16847篇
耳鼻咽喉   55165篇
儿科学   125835篇
妇产科学   106027篇
基础医学   619030篇
口腔科学   110726篇
临床医学   366977篇
内科学   710322篇
皮肤病学   99232篇
神经病学   339445篇
特种医学   156105篇
外国民族医学   556篇
外科学   604640篇
综合类   122313篇
现状与发展   24篇
一般理论   2440篇
预防医学   342832篇
眼科学   91878篇
药学   278918篇
  27篇
中国医学   11496篇
肿瘤学   191525篇
  2021年   55778篇
  2020年   35524篇
  2019年   58547篇
  2018年   73130篇
  2017年   55842篇
  2016年   61618篇
  2015年   75244篇
  2014年   109637篇
  2013年   175323篇
  2012年   112480篇
  2011年   115543篇
  2010年   122572篇
  2009年   124996篇
  2008年   101062篇
  2007年   106683篇
  2006年   116000篇
  2005年   111215篇
  2004年   112429篇
  2003年   102520篇
  2002年   91826篇
  2001年   130714篇
  2000年   124943篇
  1999年   119037篇
  1998年   68420篇
  1997年   65509篇
  1996年   63221篇
  1995年   58824篇
  1994年   53127篇
  1993年   49453篇
  1992年   87885篇
  1991年   84685篇
  1990年   81303篇
  1989年   78984篇
  1988年   73723篇
  1987年   72066篇
  1986年   68819篇
  1985年   68021篇
  1984年   59166篇
  1983年   53122篇
  1982年   45653篇
  1981年   42722篇
  1980年   40204篇
  1979年   51917篇
  1978年   43182篇
  1977年   38392篇
  1976年   35801篇
  1975年   34909篇
  1974年   38581篇
  1973年   37211篇
  1972年   35021篇
排序方式: 共有10000条查询结果,搜索用时 0 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