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   3372836篇
  免费   239682篇
  国内免费   8425篇
耳鼻咽喉   45367篇
儿科学   110921篇
妇产科学   94118篇
基础医学   479264篇
口腔科学   93834篇
临床医学   310839篇
内科学   658455篇
皮肤病学   78954篇
神经病学   276068篇
特种医学   128712篇
外国民族医学   964篇
外科学   496023篇
综合类   69057篇
现状与发展   7篇
一般理论   1447篇
预防医学   266027篇
眼科学   75945篇
药学   246063篇
  12篇
中国医学   6467篇
肿瘤学   182399篇
  2019年   26437篇
  2018年   36778篇
  2017年   28342篇
  2016年   32422篇
  2015年   36828篇
  2014年   50720篇
  2013年   76915篇
  2012年   102332篇
  2011年   108560篇
  2010年   64988篇
  2009年   62480篇
  2008年   101931篇
  2007年   108446篇
  2006年   109663篇
  2005年   105771篇
  2004年   101803篇
  2003年   98123篇
  2002年   94826篇
  2001年   156298篇
  2000年   159949篇
  1999年   135104篇
  1998年   39152篇
  1997年   34967篇
  1996年   35425篇
  1995年   34083篇
  1994年   31419篇
  1993年   29475篇
  1992年   106244篇
  1991年   103126篇
  1990年   99912篇
  1989年   96441篇
  1988年   88946篇
  1987年   87163篇
  1986年   82172篇
  1985年   78310篇
  1984年   58899篇
  1983年   50245篇
  1982年   29966篇
  1981年   26937篇
  1979年   53030篇
  1978年   37960篇
  1977年   32208篇
  1976年   29793篇
  1975年   31904篇
  1974年   38013篇
  1973年   36666篇
  1972年   34517篇
  1971年   32089篇
  1970年   29859篇
  1969年   28504篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
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   
83.
84.
85.
86.
87.

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   
88.
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   
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