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   4225541篇
  免费   331480篇
  国内免费   13968篇
耳鼻咽喉   58717篇
儿科学   134926篇
妇产科学   110569篇
基础医学   651794篇
口腔科学   113690篇
临床医学   382509篇
内科学   762806篇
皮肤病学   106201篇
神经病学   350571篇
特种医学   163729篇
外国民族医学   503篇
外科学   648102篇
综合类   119282篇
现状与发展   23篇
一般理论   2570篇
预防医学   353403篇
眼科学   98950篇
药学   294914篇
  26篇
中国医学   11327篇
肿瘤学   206377篇
  2021年   56131篇
  2020年   35610篇
  2019年   58749篇
  2018年   74032篇
  2017年   56479篇
  2016年   62510篇
  2015年   75529篇
  2014年   110047篇
  2013年   175194篇
  2012年   121543篇
  2011年   127083篇
  2010年   125584篇
  2009年   126904篇
  2008年   113176篇
  2007年   120544篇
  2006年   129163篇
  2005年   124313篇
  2004年   124548篇
  2003年   114845篇
  2002年   104111篇
  2001年   149696篇
  2000年   144545篇
  1999年   134331篇
  1998年   70120篇
  1997年   66236篇
  1996年   64432篇
  1995年   59703篇
  1994年   53786篇
  1993年   50049篇
  1992年   96051篇
  1991年   92647篇
  1990年   89050篇
  1989年   86817篇
  1988年   80018篇
  1987年   78513篇
  1986年   73855篇
  1985年   72976篇
  1984年   61663篇
  1983年   55429篇
  1982年   46018篇
  1981年   43122篇
  1980年   40509篇
  1979年   53099篇
  1978年   44031篇
  1977年   38883篇
  1976年   36266篇
  1975年   36272篇
  1974年   39408篇
  1973年   37633篇
  1972年   35245篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
13.
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   
14.
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   
15.
16.
17.
18.

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   
19.
20.
ABSTRACT

Objective

To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline.  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