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   3597122篇
  免费   264235篇
  国内免费   8757篇
耳鼻咽喉   49208篇
儿科学   119226篇
妇产科学   100314篇
基础医学   505644篇
口腔科学   102596篇
临床医学   326610篇
内科学   700620篇
皮肤病学   82943篇
神经病学   295372篇
特种医学   139897篇
外国民族医学   1131篇
外科学   537711篇
综合类   79598篇
现状与发展   6篇
一般理论   1435篇
预防医学   280041篇
眼科学   82073篇
药学   265860篇
  10篇
中国医学   6976篇
肿瘤学   192843篇
  2018年   37910篇
  2017年   29348篇
  2016年   33721篇
  2015年   38344篇
  2014年   52788篇
  2013年   80062篇
  2012年   106429篇
  2011年   112482篇
  2010年   67667篇
  2009年   64821篇
  2008年   105850篇
  2007年   112186篇
  2006年   114058篇
  2005年   109833篇
  2004年   106677篇
  2003年   102684篇
  2002年   99579篇
  2001年   167741篇
  2000年   172406篇
  1999年   145898篇
  1998年   42204篇
  1997年   37707篇
  1996年   37726篇
  1995年   36616篇
  1994年   33898篇
  1993年   31869篇
  1992年   116283篇
  1991年   112802篇
  1990年   109535篇
  1989年   106130篇
  1988年   97892篇
  1987年   96162篇
  1986年   90940篇
  1985年   87227篇
  1984年   65329篇
  1983年   55831篇
  1982年   33117篇
  1981年   29728篇
  1979年   59856篇
  1978年   41976篇
  1977年   35679篇
  1976年   33297篇
  1975年   35473篇
  1974年   42458篇
  1973年   40504篇
  1972年   37850篇
  1971年   35362篇
  1970年   32586篇
  1969年   31140篇
  1968年   28477篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
91.
92.
93.
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   
94.
95.
96.
97.
98.

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   
99.
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   
100.
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