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   6795篇
  免费   422篇
  国内免费   63篇
耳鼻咽喉   34篇
儿科学   165篇
妇产科学   266篇
基础医学   462篇
口腔科学   141篇
临床医学   516篇
内科学   1152篇
皮肤病学   64篇
神经病学   516篇
特种医学   186篇
外科学   749篇
综合类   153篇
预防医学   1582篇
眼科学   107篇
药学   234篇
  1篇
中国医学   8篇
肿瘤学   944篇
  2024年   6篇
  2023年   298篇
  2022年   482篇
  2021年   464篇
  2020年   657篇
  2019年   350篇
  2018年   305篇
  2017年   360篇
  2016年   350篇
  2015年   358篇
  2014年   661篇
  2013年   426篇
  2012年   272篇
  2011年   243篇
  2010年   400篇
  2009年   358篇
  2008年   157篇
  2007年   141篇
  2006年   131篇
  2005年   109篇
  2004年   95篇
  2003年   76篇
  2002年   67篇
  2001年   53篇
  2000年   46篇
  1999年   73篇
  1998年   57篇
  1997年   42篇
  1996年   43篇
  1995年   42篇
  1994年   25篇
  1993年   18篇
  1992年   21篇
  1991年   13篇
  1990年   11篇
  1989年   9篇
  1988年   12篇
  1987年   14篇
  1986年   17篇
  1985年   7篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   3篇
  1978年   1篇
  1977年   2篇
  1976年   1篇
排序方式: 共有7280条查询结果,搜索用时 156 毫秒
1.
We present an automated approach to detect and longitudinally track skin lesions on 3D total-body skin surface scans. The acquired 3D mesh of the subject is unwrapped to a 2D texture image, where a trained objected detection model, Faster R-CNN, localizes the lesions within the 2D domain. These detected skin lesions are mapped back to the 3D surface of the subject and, for subjects imaged multiple times, we construct a graph-based matching procedure to longitudinally track lesions that considers the anatomical correspondences among pairs of meshes and the geodesic proximity of corresponding lesions and the inter-lesion geodesic distances.We evaluated the proposed approach using 3DBodyTex, a publicly available dataset composed of 3D scans imaging the coloured skin (textured meshes) of 200 human subjects. We manually annotated locations that appeared to the human eye to contain a pigmented skin lesion as well as tracked a subset of lesions occurring on the same subject imaged in different poses. Our results, when compared to three human annotators, suggest that the trained Faster R-CNN detects lesions at a similar performance level as the human annotators. Our lesion tracking algorithm achieves an average matching accuracy of 88% on a set of detected corresponding pairs of prominent lesions of subjects imaged in different poses, and an average longitudinal accuracy of 71% when encompassing additional errors due to lesion detection. As there currently is no other large-scale publicly available dataset of 3D total-body skin lesions, we publicly release over 25,000 3DBodyTex manual annotations, which we hope will further research on total-body skin lesion analysis.  相似文献   
2.
3.
4.
BackgroundAdolescence is a key stage of the life course when lifelong health behaviours and attitudes to health care can be established. Poor experience of consultations with a general practitioner (GP) is common among adolescents, but little is known about whether poor experience in this group is associated with worse health status or outcomes. This study aimed to investigate this association with data from the 2014 Health Behaviour in School-Aged Children (HBSC) survey (England).MethodsWe used logistic regression to analyse data for 5335 participants aged 10–17 years in the HBSC survey. Four aspects of recent GP experience were studied: feeling at ease, being treated with respect, quality of GP explanation, and feeling able to talk about personal matters. Five dichotomised measures of health status or outcome were used (ever self-harmed; fair or poor self-reported health; frequent [at least weekly] low mood, sleeping problems, or headaches). We adjusted for participants’ sex, age, ethnicity, and family affluence score. Of 5178 participants, 1187 (23%) had not visited their GP within the past year and were excluded from the analysis.FindingsOf 3991 adolescents, 3632 (91%) felt treated with respect, 2091 (52%) could talk about personal matters, 1600 (40%) were satisfied with explanations, and 1221 (31%) felt at ease. Participants who reported poor experience of GP care were more likely to have poor health outcomes than were those who reported a good experience. For example, adolescents who did not feel at ease with their GP were more likely to report self-harm (adjusted odds ratio [AOR] 2·65, 95% CI 1·69–4·15; fair or poor health 1·64, 1·28–2·10; low mood 1·51, 1·25–1·82) and sleeping problems (1·41, 1·19–1·66). All GP indicators were associated with self-harm (AOR range 1·64–2·70; quality of GP explanation p=0·006, all others p<0·001) and feeling low (1·46–2·11, all p<0·001). The association with GP experience was less consistent for the other three health outcomes.InterpretationThis cross-sectional, observational study demonstrates that young people who report worse health symptoms, typically also report a poor experience of care. Further research is needed to investigate whether GP experience influences health outcomes—suggesting that improving GP experience might improve health outcomes in this group—or whether poor health status leads to more negative perceptions of care.FundingNone.  相似文献   
5.
ObjectiveHospitalization-associated disability [HAD, ie, the loss of ability to perform ≥1 basic activities of daily living (ADLs) independently at discharge] is a frequent condition among older patients. The present study assessed whether a simple inpatient exercise program decreases HAD incidence in acutely hospitalized very old patients.DesignIn this randomized controlled trial (Activity in Geriatric Acute Care) participants were assigned to a control or intervention group and were assessed at baseline, admission, discharge, and 3 months thereafter.Setting and ParticipantsIn total, 268 patients (mean age 88 years, range 75–102) admitted to an acute care for older patients unit of a public hospital were randomized to a control (n = 125) or intervention (exercise) group (n = 143).MethodsBoth groups received usual care, and patients in the intervention group also performed simple supervised exercises (walking and rising from a chair, for a total duration of ∼20 minutes/day). We measured ADL function (Katz index) and incident HAD at discharge and after 3 months (primary outcome) and Short Physical Performance Battery, ambulatory capacity, number of falls, rehospitalization, and death during a 3-month follow-up (secondary outcomes).ResultsMedian duration of hospitalization was 7 days (interquartile range 4 days). The intervention group had a lower risk of HAD with reference to both baseline [odds ratio (OR) 0.36; 95% confidence interval (CI) 0.17–0.76, P = .007] and admission (OR 0.29; 95% CI 0.10–0.89, P = .030). A trend toward an improved ADL function at discharge vs admission was found in the intervention group compared with controls (OR 0.32; 95% CI ‒0.04 to 0.68; P = .083). No between-group differences were noted for the other endpoints (all P > .05).Conclusion and ImplicationsA simple inpatient exercise program decreases risk of HAD in acutely hospitalized, very old patients.  相似文献   
6.
7.
8.
BackgroundPreschool age is a critical stage of postural balance development. Posturography normative data during this age are crucial for surveillance of postural balance and for the timely diagnosis of any dysfunction. The aim of this study was to provide normative data, specific to Tunisian preschoolers, according to age and gender, and to examine gender- and age-related differences in postural balance.Research questionAre there postural balance gender- and age-related differences in Tunisian preschoolers?MethodsThe study included 410 (205 boys and 205 girls) preschool children aged between 4- and 5-year-old selected within a large geographic area of Tunisia. Postural balance was assessed using a stabilometric platform under 4 sensory conditions. The mean center of pressure velocity (CoP-V) parameter was selected for analysis. Differences between gender and age groups were analysed using the Mann–Whitney U. Normative data were expressed in percentiles.ResultsSignificant gender effect was found in conditions where sensory inputs are most challenged with a significantly smaller mean CoP-V in girls compared to boys (p < 0.05). Moreover, 5-year-old children had significantly better postural balance than 4-year-old ones in almost all conditions (p < 0.05).SignificanceThe normative data established for Tunisian preschoolers provide useful comparative data for pediatricians, teachers and coaches for the early evaluation and monitoring of postural balance during this age. Gender and age-related differences should be considered in this population.  相似文献   
9.
10.
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