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   3805831篇
  免费   343321篇
  国内免费   39107篇
耳鼻咽喉   50301篇
儿科学   115247篇
妇产科学   91329篇
基础医学   589898篇
口腔科学   100343篇
临床医学   365753篇
内科学   662123篇
皮肤病学   95629篇
神经病学   316867篇
特种医学   149989篇
外国民族医学   522篇
外科学   566425篇
综合类   171734篇
现状与发展   108篇
一般理论   2303篇
预防医学   318134篇
眼科学   89059篇
药学   277258篇
  455篇
中国医学   33908篇
肿瘤学   190874篇
  2022年   36680篇
  2021年   72421篇
  2020年   50861篇
  2019年   73426篇
  2018年   85771篇
  2017年   69292篇
  2016年   74098篇
  2015年   93776篇
  2014年   131745篇
  2013年   194898篇
  2012年   120397篇
  2011年   123154篇
  2010年   139499篇
  2009年   138630篇
  2008年   99484篇
  2007年   101338篇
  2006年   110871篇
  2005年   105742篇
  2004年   101037篇
  2003年   91290篇
  2002年   78737篇
  2001年   117767篇
  2000年   111562篇
  1999年   108749篇
  1998年   70046篇
  1997年   67445篇
  1996年   64950篇
  1995年   60549篇
  1994年   54156篇
  1993年   49967篇
  1992年   75410篇
  1991年   71942篇
  1990年   67999篇
  1989年   66360篇
  1988年   61444篇
  1987年   59999篇
  1986年   56628篇
  1985年   56518篇
  1984年   50704篇
  1983年   45964篇
  1982年   42634篇
  1981年   40084篇
  1980年   37734篇
  1979年   41864篇
  1978年   36603篇
  1977年   33143篇
  1976年   30470篇
  1975年   29043篇
  1974年   30293篇
  1973年   29050篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.

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   
22.
Patients with mechanic ankle instability experience increased tibiotalar and subtalar joint laxity. However, in vivo joint kinematics in functional ankle instability (FAI) patients and lateral ankle sprain (LAS) copers, especially during dynamic activities, are poorly understood. Ten FAI patients, 10 LAS copers, and 10 healthy controls were included in this study. A dual fluoroscopic imaging system was used to analyze the tibiotalar and subtalar joint kinematics during stair descent. Five key poses of stair descent were analyzed. Kinematic data from six degrees of freedom were calculated utilizing a solid modeling software. The range of motion and joint positions in each degree of freedom were compared among the three groups. The tibiotalar joints of FAI patients and LAS copers were significantly more inverted than those of healthy controls during the foot strike (p = 0.016, = 0.264). The subtalar joints of FAI patients were significantly more anteriorly translated (pose 2, p = 0.003, = 0.352; pose 3, p < 0.001, = 0.454; pose 4, p = 0.004, = 0.334), inverted (pose 4, p = 0.027, = 0.234; pose 5,p = 0.034, = 0.221), and externally rotated (pose 4, p = 0.037, = 0.217; pose 5; p = 0.004, = 0.331) than those of healthy controls during the mid‐stance and the heel off. The FAI patients showed excessive tibiotalar inversion and subtalar joint hypermobility during stair descent. Meanwhile, the LAS copers maintained subtalar joint stability, and only showed excessive tibiotalar inversion in foot strike. These data provide insight into the mechanisms behind the development of FAI after initial LAS. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1860–1867, 2019  相似文献   
23.
24.
25.
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   
26.
27.
28.
29.
30.
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