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   1273篇
  免费   97篇
  国内免费   6篇
耳鼻咽喉   11篇
儿科学   16篇
妇产科学   48篇
基础医学   192篇
口腔科学   30篇
临床医学   118篇
内科学   415篇
皮肤病学   17篇
神经病学   91篇
特种医学   47篇
外科学   102篇
综合类   4篇
一般理论   1篇
预防医学   86篇
眼科学   21篇
药学   82篇
中国医学   3篇
肿瘤学   92篇
  2024年   1篇
  2023年   14篇
  2022年   38篇
  2021年   64篇
  2020年   25篇
  2019年   57篇
  2018年   69篇
  2017年   42篇
  2016年   39篇
  2015年   46篇
  2014年   76篇
  2013年   106篇
  2012年   132篇
  2011年   113篇
  2010年   54篇
  2009年   59篇
  2008年   63篇
  2007年   79篇
  2006年   51篇
  2005年   67篇
  2004年   60篇
  2003年   46篇
  2002年   37篇
  2001年   4篇
  2000年   3篇
  1999年   4篇
  1998年   4篇
  1997年   2篇
  1996年   2篇
  1995年   3篇
  1994年   3篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1982年   1篇
  1981年   1篇
排序方式: 共有1376条查询结果,搜索用时 15 毫秒
61.
62.

Introduction and objectives

Left atrial dysfunction in aortic stenosis may precede atrial enlargement and predict the occurrence of atrial fibrillation (AF). To test this hypothesis, we assessed left atrial function and determined its impact on the incidence of AF after aortic valve replacement.

Methods

A total of 149 severe aortic stenosis patients (74 ± 8.6 years, 51% men) with no prior AF were assessed using speckle-tracking echocardiography. Left atrial function was evaluated using peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and phasic left atrial volumes. The occurrence of AF was monitored in 114 patients from surgery until hospital discharge.

Results

In multiple linear regression, PALS and PACS were inversely correlated with left atrial dilation, left ventricular hypertrophy, and diastolic function. Atrial fibrillation occurred in 36 patients within a median time of 3 days [interquartile range, 1-4] after aortic valve replacement. In multiple Cox regression, PALS and PACS were independently associated with the incidence of AF (HR, 0.946; 95%CI, 0.910-0.983; P = .005 and HR, 0.932; 95%CI, 0.883-0.984; P = .011, respectively), even after further adjustment for left atrial dimensions. Both reduced PALS and PACS were associated with the incidence of AF in patients with nondilated left atria (P value for the interaction of PALS with left atrial dimensions = .013).

Conclusions

In severe aortic stenosis, left atrial dysfunction predicted the incidence of postoperative AF independently of left atrial dilation, suggesting that speckle-tracking echocardiography before surgery may help in risk stratification, particularly in patients with nondilated left atria.Full English text available from: www.revespcardiol.org/en  相似文献   
63.
The purpose of this study was to verify the efficacy of a Perceptual-Motor Competences Training Program upon the performance on UFOV of an experimental active group of elderly drivers. Program tasks were conceived to force subjects to divide their attention for central and peripheral stimuli, using a visual strategy of gazing at an anchor-point and, from there, detect important clues on peripheral visual field. For this purpose, almost all tasks were performed on groups of two, being one responsible for testing the other and switching functions from time to time (for instance, dropping one of two juggling handkerchiefs hold apart, one in each tester hand, with the partner having to detect which was dropped and react as quick as possible, catching it before it felt to the floor). We found a significant improvement in the capacity of dividing attention for central and peripheral stimuli under a visual environment full of distractors (selective attention UFOV test) following the Program, as well as a significant reduction on the category of risk (component based upon the three UFOV subtests results), which evidence very clearly the benefits of this training program on the elderly experimental group and its potential to reduce their risk of being involved in car accidents, on their fault, due to perceptual reasons.  相似文献   
64.
65.
66.
Poor ventilation at day care centres (DCCs) was already reported, although its effects on attending children are not clear. This study aimed to evaluate the association between wheezing in children and indoor CO2 (a ventilation surrogate marker) in DCC and to identify behaviours and building characteristics potentially related to CO2. In phase I, 45 DCCs from Lisbon and Oporto (Portugal) were selected through a proportional stratified random sampling. In phase II, 3 months later, 19 DCCs were further reassessed after cluster analysis for the greatest difference comparison. In both phases, children’s respiratory health was assessed by ISAAC-derived questionnaires. Indoor CO2 concentrations and building characteristics of the DCC were evaluated in both phases, using complementary methods. Mixed effect models were used to analyze the data. In phase I, which included 3,186 children (mean age 3.1?±?1.5 years), indoor CO2 concentration in the DCC rooms was associated with reported wheezing in the past 12 months (27.5 %) (adjusted odds ratio (OR) for each increase of 200 ppm 1.04, 95 % CI 1:01 to 1:07). In phase II, the association in the subsample of 1,196 children seen in 19 out of the initial 45 DCCs was not significant (adjusted OR 1.02, 95 % CI 0.96 to 1.08). Indoor CO2 concentration was inversely associated with the practices of opening windows and internal doors and with higher wind velocity. A positive trend was observed between CO2 and prevalence of reported asthma (4.7 %). Conclusion: Improved ventilation is needed to achieve a healthier indoor environment in DCC.  相似文献   
67.
Silk fibroin (SF) hydrogels can be obtained via self‐assembly, but this process takes several days or weeks, being unfeasible to produce cell carrier hydrogels. In this work, a phospholipid, namely, 1,2‐dimyristoyl‐sn‐glycero‐3‐phospho‐(1′‐rac‐glycerol) sodium salt (DMPG), was used to induce and accelerate the gelation process of SF solutions. Due to the amphipathic nature and negative charge of DMPG, electrostatic and hydrophobic interactions between the phospholipids and SF chains will occur, inducing the structural transition of SF chains to the beta sheet and consequently a rapid gel formation is observed (less than 50 min). Moreover, the gelation time can be controlled by varying the lipid concentration. To assess the potential of the hydrogels as cell carriers, several mammalian cell lines, including L929, NIH/3T3, SaOS‐2, and CaSki, were encapsulated into the hydrogel. The silk‐based hydrogels supported the normal growth of fibroblasts, corroborating their cytocompatibility. Interestingly, an inhibition in the growth of cancer‐derived cell lines was observed. Therefore, DMPG‐induced SF hydrogels can be successfully used as a 3D platform for in situ cell encapsulation, opening promising opportunities in biomedical applications, such as in cell therapies and tissue regeneration.  相似文献   
68.
Anxiety and depression are frequent among patients with breast cancer (BCa). Evidence of the persistence and recovery from these conditions and their determinants is scarce. We describe the occurrence of clinically significant anxiety and depression symptoms and their associated factors among BCa patients. A total of 506 women admitted in 2012 at the Portuguese Institute of Oncology of Porto were evaluated before treatment and after one, three, and five years (7.9% attrition rate). The five-year prevalence of anxiety and/or depression (Hospital Anxiety and Depression Scale, subscores ≥ 11) was 55.4%. The peak prevalence for anxiety was before treatment (38.0%), and after one year for depression (13.1%). One in five patients with anxiety/depression at baseline had persistent anxiety/depression over time, while only 11% and 22% recovered permanently from anxiety and depression, respectively, during the first year. Higher education, higher income, practicing physical activity, and adequate fruit and vegetable intake were protective factors against anxiety and/or depression. Loss of job and income, anxiolytics and antidepressants, cancer-related neuropathic pain, and mastectomy were associated with higher odds of anxiety and/or depression. These results highlight the importance of monitoring anxiety/depression during the first five years after cancer diagnosis and identify factors associated with these conditions.  相似文献   
69.
70.
IntroductionHealth professionals should work with the notion of risk involved in the health care process. Dental practice risk is of particular interest because it encompasses both aesthetic and functional components. Focusing on guidelines suggested by the World Health Organization and objectives on patient safety, this study has 2 objectives: to present Portuguese medicolegal data on corporal damage evaluation related to iatrogenic sequelae during dental practice and to present updated evidence on patient safety.Materials and methodsA retrospective study was performed by analysing data from the database of the Laboratory of Forensic Dentistry of the Faculty of Medicine, University of Coimbra, Portugal, from 2013 to 2018.ResultsOne hundred seven medicolegal files were selected according to the inclusion and exclusion criteria. Iatrogenic sequelae (73.8%, 79 out of 107) were categorised as risks (60 out of 79) and malpractice (19 out of 79). The risk was associated mostly with mandibular dysfunction and orthodontic treatment (62.2%). Malpractice was mostly associated with neurological deficit and implant rehabilitation (47.4%).Discussion and conclusionGreater attention to these data by professionals was emphasised, especially when considering patient safety and health care quality. This article presents the Portuguese data on professional liability in the field of dental practice, categorising iatrogenic sequelae into risks and malpractice, as well as the oral rehabilitation procedure and timeline.  相似文献   
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