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   1740篇
  免费   158篇
  国内免费   1篇
耳鼻咽喉   20篇
儿科学   75篇
妇产科学   28篇
基础医学   305篇
口腔科学   35篇
临床医学   136篇
内科学   363篇
皮肤病学   5篇
神经病学   113篇
特种医学   43篇
外科学   292篇
综合类   17篇
预防医学   116篇
眼科学   24篇
药学   71篇
肿瘤学   256篇
  2021年   9篇
  2020年   22篇
  2019年   18篇
  2018年   27篇
  2017年   22篇
  2016年   41篇
  2015年   22篇
  2014年   33篇
  2013年   56篇
  2012年   59篇
  2011年   79篇
  2010年   47篇
  2009年   39篇
  2008年   64篇
  2007年   59篇
  2006年   86篇
  2005年   84篇
  2004年   74篇
  2003年   41篇
  2002年   72篇
  2001年   75篇
  2000年   52篇
  1999年   48篇
  1998年   41篇
  1997年   22篇
  1996年   27篇
  1995年   30篇
  1994年   18篇
  1993年   15篇
  1992年   57篇
  1991年   46篇
  1990年   37篇
  1989年   40篇
  1988年   37篇
  1987年   30篇
  1986年   46篇
  1985年   47篇
  1984年   41篇
  1983年   28篇
  1982年   18篇
  1980年   12篇
  1979年   22篇
  1978年   13篇
  1977年   16篇
  1975年   14篇
  1974年   14篇
  1973年   12篇
  1972年   13篇
  1971年   11篇
  1968年   9篇
排序方式: 共有1899条查询结果,搜索用时 14 毫秒
31.
During the initial hospitalization, ventricular fibrillation (VF) developed in 6 metoprolol-treated patients (0.9%) vs 17 placebo-treated patients (2.4%) after inclusion in the study (p = 0.035). There were 6 episodes of VF in the metoprolol group compared with 41 episodes in the placebo group (p less than 0.001). During the same period, 14 metoprolol-treated patients had treated ventricular tachycardia vs 26 placebo-treated patients (p = 0.076). Similar favorable results were found when the incidence of severe ventricular arrhythmias during the first rehospitalization within the 3-month double-blind treatment period was analyzed.  相似文献   
32.
33.
34.
We developed a novel titanium coating that has applications for preventing infection-related implant failures in dentistry and orthopedics. The coating incorporates an antimicrobial peptide, GL13K, derived from parotid secretory protein, which has been previously shown to be bactericidal and bacteriostatic in solution. We characterized the resulting physicochemical properties, resistance to degradation, activity against Porphyromonas gingivalis and in vitro cytocompatibility. Porphyromonas gingivalis is a pathogen associated with dental peri-implantitis, an inflammatory response to bacteria resulting in bone loss and implant failure. Our surface modifications obtained a homogeneous, highly hydrophobic and strongly anchored GL13K coating that was resistant to mechanical, thermochemical and enzymatic degradation. The GL13K coatings had a bactericidal effect and thus significantly reduced the number of viable bacteria compared to control surfaces. Finally, adequate proliferation of osteoblasts and human gingival fibroblasts demonstrated the GL13K coating’s cytocompatibility. The robustness, antimicrobial activity and cytocompatibility of GL13K-biofunctionalized titanium make it a promising candidate for sustained inhibition of bacterial biofilm growth. This surface chemistry provides a basis for development of multifunctional bioactive surfaces to reduce patient morbidities and improve long-term clinical efficacy of metallic dental and orthopedic implants.  相似文献   
35.
Objective. To investigate the associations between oral sugar clearance and the prevalence of dental decay. Material and Methods. A total of 92 (44 F, 48 M) 71-year-old subjects in Göteborg, Sweden were consecutively chosen from a representative cohort study. The subjects were examined for: 1) caries-related status, 2) oral function, 3) salivary conditions, 4) cariogenic micro-organisms, and 5) oral sugar clearance. A factor analysis was used to investigate the possible existence of latent variables within these five areas. The latent variables from the factor analyses were used to study the associations between clearance and caries in multivariate regression models. Results. Only one latent variable relating to oral sugar clearance was found. In the regression model with the latent variable related to oral sugar clearance as a dependent variable and gender plus the latent variables related to oral function and salivary conditions as an independent variable, there were associations with gender and some latent variables reflecting oral function and one reflecting glucose in saliva (R2=0.20/0.17). Three latent variables relating to caries-related status were found and these were associated with the number of teeth, the percentage of filled tooth surfaces, and the percentage of decayed tooth surfaces (DS%). In the regression analysis using the latent variable associated with DS% as a dependent variable, this variable was related to the latent variables of oral sugar clearance and to some reflecting oral function, as well as glucose in saliva (R2=0.28). Conclusions: Oral sugar clearance appears to be independently associated with the prevalence of dental caries in the elderly.  相似文献   
36.
37.
A huge number of risk assessment tools have been developed. Far from all have been validated in external studies, more of them have absence of methodological and transparent evidence, and few are integrated in national guidelines. Therefore, we performed a systematic review to provide an overview of existing valid and reliable risk assessment tools for prediction of osteoporotic fractures. Additionally, we aimed to determine if the performance of each tool was sufficient for practical use, and last, to examine whether the complexity of the tools influenced their discriminative power. We searched PubMed, Embase, and Cochrane databases for papers and evaluated these with respect to methodological quality using the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS) checklist. A total of 48 tools were identified; 20 had been externally validated, however, only six tools had been tested more than once in a population‐based setting with acceptable methodological quality. None of the tools performed consistently better than the others and simple tools (i.e., the Osteoporosis Self‐assessment Tool [OST], Osteoporosis Risk Assessment Instrument [ORAI], and Garvan Fracture Risk Calculator [Garvan]) often did as well or better than more complex tools (i.e., Simple Calculated Risk Estimation Score [SCORE], WHO Fracture Risk Assessment Tool [FRAX], and Qfracture). No studies determined the effectiveness of tools in selecting patients for therapy and thus improving fracture outcomes. High‐quality studies in randomized design with population‐based cohorts with different case mixes are needed.  相似文献   
38.
39.
Attention deficit hyperactivity disorder (ADHD) is a common developmental disorder. The present study tested the hypotheses that children with ADHD, particularly those exhibiting severe hyperactivity and impulsivity, have a different stress reaction (measured by salivary cortisol) during a dental recall visit and are more dentally anxious than children in a control group. Eighteen children with ADHD and a control group of 71 children, all 13 yr of age, underwent a clinical dental examination and completed the Corah Dental Anxiety Scale (CDAS). Four saliva samples were gathered for analysis of cortisol: one prior to dental examination, one after, and two the following morning. The subgroup ADHD with hyperactivity/impulsivity had statistically significantly lower cortisol levels than the control group 30 min after awakening. When cortisol values were plotted on a timeline, this subgroup always had lower cortisol concentrations than children in the control group. There was a significant correlation between CDAS scores and cortisol concentrations prior to the dental examination in both the ADHD and the control group. Behavioral expressions of anxiety in children with ADHD may be different from those in other children, not only due to the characteristics of their disorder, but also because of lower stress reactivity.  相似文献   
40.
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