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   2224760篇
  免费   167145篇
  国内免费   7372篇
耳鼻咽喉   29710篇
儿科学   71300篇
妇产科学   60056篇
基础医学   308760篇
口腔科学   62087篇
临床医学   200005篇
内科学   441584篇
皮肤病学   52163篇
神经病学   177356篇
特种医学   90610篇
外国民族医学   473篇
外科学   343774篇
综合类   49436篇
现状与发展   3篇
一般理论   656篇
预防医学   169062篇
眼科学   48870篇
药学   165291篇
  10篇
中国医学   4557篇
肿瘤学   123514篇
  2018年   22521篇
  2017年   17813篇
  2016年   20968篇
  2015年   23367篇
  2014年   32302篇
  2013年   48006篇
  2012年   61337篇
  2011年   65491篇
  2010年   40006篇
  2009年   38542篇
  2008年   61122篇
  2007年   65288篇
  2006年   66756篇
  2005年   64025篇
  2004年   61305篇
  2003年   59469篇
  2002年   56985篇
  2001年   112406篇
  2000年   115795篇
  1999年   96655篇
  1998年   26887篇
  1997年   23914篇
  1996年   24693篇
  1995年   24278篇
  1994年   22461篇
  1993年   21144篇
  1992年   77218篇
  1991年   74876篇
  1990年   72694篇
  1989年   69775篇
  1988年   63951篇
  1987年   62653篇
  1986年   59090篇
  1985年   56468篇
  1984年   42098篇
  1983年   35416篇
  1982年   21089篇
  1981年   18670篇
  1980年   17672篇
  1979年   37848篇
  1978年   26626篇
  1977年   23026篇
  1976年   20676篇
  1975年   22332篇
  1974年   26127篇
  1973年   25107篇
  1972年   23511篇
  1971年   21853篇
  1970年   20010篇
  1969年   19005篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.  相似文献   
4.
5.
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   
6.
7.
8.

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   
9.
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   
10.
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