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   3449029篇
  免费   282935篇
  国内免费   13381篇
耳鼻咽喉   47029篇
儿科学   109472篇
妇产科学   89617篇
基础医学   549162篇
口腔科学   93205篇
临床医学   314416篇
内科学   609198篇
皮肤病学   91286篇
神经病学   294803篇
特种医学   134288篇
外国民族医学   288篇
外科学   525838篇
综合类   102555篇
现状与发展   24篇
一般理论   2374篇
预防医学   295629篇
眼科学   78414篇
药学   235696篇
  27篇
中国医学   9354篇
肿瘤学   162670篇
  2021年   55142篇
  2020年   35109篇
  2019年   58056篇
  2018年   71387篇
  2017年   54424篇
  2016年   59873篇
  2015年   74011篇
  2014年   108105篇
  2013年   173280篇
  2012年   94858篇
  2011年   95471篇
  2010年   117155篇
  2009年   121368篇
  2008年   82438篇
  2007年   85898篇
  2006年   95721篇
  2005年   91407篇
  2004年   93012篇
  2003年   83603篇
  2002年   73421篇
  2001年   102629篇
  2000年   95331篇
  1999年   95337篇
  1998年   64584篇
  1997年   62640篇
  1996年   60796篇
  1995年   56214篇
  1994年   50470篇
  1993年   47130篇
  1992年   67631篇
  1991年   64877篇
  1990年   61566篇
  1989年   60697篇
  1988年   56531篇
  1987年   55304篇
  1986年   52713篇
  1985年   52317篇
  1984年   48236篇
  1983年   44381篇
  1982年   41730篇
  1981年   39463篇
  1980年   37189篇
  1979年   40718篇
  1978年   36293篇
  1977年   32877篇
  1976年   30171篇
  1975年   29037篇
  1974年   30536篇
  1973年   29638篇
  1972年   27901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