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   2222300篇
  免费   166946篇
  国内免费   7378篇
耳鼻咽喉   29695篇
儿科学   71202篇
妇产科学   60000篇
基础医学   308516篇
口腔科学   62014篇
临床医学   199603篇
内科学   441079篇
皮肤病学   52150篇
神经病学   177141篇
特种医学   90444篇
外国民族医学   472篇
外科学   343548篇
综合类   49392篇
现状与发展   3篇
一般理论   657篇
预防医学   168838篇
眼科学   48838篇
药学   165129篇
  10篇
中国医学   4560篇
肿瘤学   123333篇
  2018年   22480篇
  2017年   17790篇
  2016年   20944篇
  2015年   23336篇
  2014年   32246篇
  2013年   47905篇
  2012年   61214篇
  2011年   65371篇
  2010年   39955篇
  2009年   38485篇
  2008年   61018篇
  2007年   65166篇
  2006年   66612篇
  2005年   63916篇
  2004年   61183篇
  2003年   59376篇
  2002年   56889篇
  2001年   112346篇
  2000年   115723篇
  1999年   96606篇
  1998年   26859篇
  1997年   23892篇
  1996年   24660篇
  1995年   24264篇
  1994年   22436篇
  1993年   21134篇
  1992年   77172篇
  1991年   74828篇
  1990年   72636篇
  1989年   69725篇
  1988年   63904篇
  1987年   62612篇
  1986年   59032篇
  1985年   56420篇
  1984年   42058篇
  1983年   35388篇
  1982年   21066篇
  1981年   18650篇
  1980年   17652篇
  1979年   37821篇
  1978年   26598篇
  1977年   23004篇
  1976年   20654篇
  1975年   22313篇
  1974年   26102篇
  1973年   25092篇
  1972年   23490篇
  1971年   21837篇
  1970年   19999篇
  1969年   18991篇
排序方式: 共有10000条查询结果,搜索用时 0 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