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   4247807篇
  免费   333365篇
  国内免费   16922篇
耳鼻咽喉   59105篇
儿科学   137488篇
妇产科学   113592篇
基础医学   651487篇
口腔科学   116852篇
临床医学   388442篇
内科学   762393篇
皮肤病学   104448篇
神经病学   355729篇
特种医学   165135篇
外国民族医学   721篇
外科学   642359篇
综合类   123725篇
现状与发展   23篇
一般理论   2470篇
预防医学   360791篇
眼科学   98499篇
药学   297642篇
  28篇
中国医学   11986篇
肿瘤学   205179篇
  2021年   56307篇
  2020年   35851篇
  2019年   59058篇
  2018年   74349篇
  2017年   56753篇
  2016年   62669篇
  2015年   76167篇
  2014年   110743篇
  2013年   176782篇
  2012年   118488篇
  2011年   123312篇
  2010年   125349篇
  2009年   126918篇
  2008年   109437篇
  2007年   116102篇
  2006年   125274篇
  2005年   120512篇
  2004年   121053篇
  2003年   111175篇
  2002年   101011篇
  2001年   145759篇
  2000年   140324篇
  1999年   131733篇
  1998年   70204篇
  1997年   66651篇
  1996年   64604篇
  1995年   60093篇
  1994年   54316篇
  1993年   50378篇
  1992年   97012篇
  1991年   94024篇
  1990年   90573篇
  1989年   88242篇
  1988年   82184篇
  1987年   80121篇
  1986年   76582篇
  1985年   75470篇
  1984年   63915篇
  1983年   57292篇
  1982年   47182篇
  1981年   43976篇
  1980年   41273篇
  1979年   55772篇
  1978年   45553篇
  1977年   40498篇
  1976年   37978篇
  1975年   37748篇
  1974年   41446篇
  1973年   40109篇
  1972年   37711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