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   2695112篇
  免费   188207篇
  国内免费   7837篇
耳鼻咽喉   36219篇
儿科学   89441篇
妇产科学   74553篇
基础医学   378618篇
口腔科学   73159篇
临床医学   242494篇
内科学   534045篇
皮肤病学   65429篇
神经病学   222743篇
特种医学   105430篇
外国民族医学   752篇
外科学   403421篇
综合类   51229篇
现状与发展   5篇
一般理论   989篇
预防医学   201655篇
眼科学   59904篇
药学   195649篇
  8篇
中国医学   5598篇
肿瘤学   149815篇
  2021年   20829篇
  2019年   21500篇
  2018年   31212篇
  2017年   24156篇
  2016年   28361篇
  2015年   31847篇
  2014年   42850篇
  2013年   63931篇
  2012年   85637篇
  2011年   89722篇
  2010年   54041篇
  2009年   51542篇
  2008年   84052篇
  2007年   89544篇
  2006年   91293篇
  2005年   87794篇
  2004年   84382篇
  2003年   81617篇
  2002年   78792篇
  2001年   131139篇
  2000年   134039篇
  1999年   112932篇
  1998年   32102篇
  1997年   28614篇
  1996年   28757篇
  1995年   27841篇
  1994年   25465篇
  1993年   23798篇
  1992年   86298篇
  1991年   82714篇
  1990年   79957篇
  1989年   77184篇
  1988年   70495篇
  1987年   68963篇
  1986年   64477篇
  1985年   61430篇
  1984年   45653篇
  1983年   38546篇
  1982年   22888篇
  1981年   20369篇
  1979年   39819篇
  1978年   28051篇
  1977年   23764篇
  1976年   21972篇
  1975年   23519篇
  1974年   27511篇
  1973年   26051篇
  1972年   24417篇
  1971年   22621篇
  1970年   20763篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The aim of the present study was to evaluate the antimicrobial activity of two synbiotic combinations, Lactobacillus fermentum with short-chain fructooligosaccharides (FOS-LF) and Bifidobacterium longum with isomaltooligosaccharides (IMO-BL), against enterohaemorrhagic Escherichia coli O157:H7 and enteropathogenic E. coli O86. Antimicrobial activity was determined (1) by co-culturing the synbiotics and pathogens in batch cultures, and (2) with the three-stage continuous culture system (gut model), inoculated with faecal slurry from an elderly donor. In the co-culture experiments, IMO-BL was significantly inhibitory to both E. coli strains, while FOS-LF was slightly inhibitory or not inhibitory. Factors other than acid production appeared to play a role in the inhibition. In the gut models, both synbiotics effectively inhibited E. coli O157 in the first vessel, but not in vessels 2 and 3. E. coli O86 was not significantly inhibited.  相似文献   
82.
83.
84.
85.
86.

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   
87.
BackgroundThe measurement of health-related quality of life (HRQoL) provides information about the perceived burden of the health condition and treatments from a lived experience. The Brisbane Burn Scar Impact Profile (caregiver report for young children, BBSIP0–8), developed in 2013, is a proxy-report measure of burn scar-specific HRQoL. The aim of this study was to report its psychometric properties in line with an evaluative purpose.MethodsCaregivers of children up to 8 years of age at risk of burn scarring were recruited into a prospective, longitudinal cohort study. Caregivers completed the BBSIP0–8, Pediatric Quality of Life Inventory and Patient Observer Scar Assessment Scale at baseline (approximately ≥85% of the total body surface area re-epithelialised), 1–2 weeks after baseline and 1-month after baseline. Psychometric properties measured included internal consistency, test–retest reliability, validity and responsiveness.ResultsEighty-six caregivers of mostly male children (55%), of a median age (IQR) of 1 year, 10 months (2 years, 1 month) and total body surface area burn of 1.5% (3.0%) were recruited. Over one third of participants were grafted and 15% had contractures or skin tightness at baseline. Internal consistency of ten item groups ranged from 0.73 to 0.96. Hypothesised correlations of changes in the BBSIP0–8 items with changes in criterion measures supported longitudinal validity (ρ ranging from ?0.73 to 0.68). The majority of item groups had acceptable reproducibility (ICC = 0.65–0.83). The responsiveness of five item groups was supported (AUC = 0.71–0.90).ConclusionThe psychometric properties tested support the use of the BBSIP0–8 as an evaluative measure of burn scar-related health-related quality of life for children aged below eight years in the early post-acute period of rehabilitation. Further investigation at longer time period after burn injury is indicated.  相似文献   
88.
89.
90.
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