全文获取类型
收费全文 | 15216篇 |
免费 | 1226篇 |
国内免费 | 187篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 1024篇 |
妇产科学 | 128篇 |
基础医学 | 1871篇 |
口腔科学 | 183篇 |
临床医学 | 1030篇 |
内科学 | 1360篇 |
皮肤病学 | 193篇 |
神经病学 | 677篇 |
特种医学 | 175篇 |
外科学 | 706篇 |
综合类 | 1124篇 |
一般理论 | 2篇 |
预防医学 | 6017篇 |
眼科学 | 55篇 |
药学 | 1431篇 |
9篇 | |
中国医学 | 312篇 |
肿瘤学 | 287篇 |
出版年
2024年 | 17篇 |
2023年 | 220篇 |
2022年 | 699篇 |
2021年 | 1066篇 |
2020年 | 655篇 |
2019年 | 604篇 |
2018年 | 559篇 |
2017年 | 517篇 |
2016年 | 525篇 |
2015年 | 578篇 |
2014年 | 930篇 |
2013年 | 1522篇 |
2012年 | 819篇 |
2011年 | 909篇 |
2010年 | 725篇 |
2009年 | 695篇 |
2008年 | 708篇 |
2007年 | 693篇 |
2006年 | 536篇 |
2005年 | 496篇 |
2004年 | 402篇 |
2003年 | 367篇 |
2002年 | 267篇 |
2001年 | 253篇 |
2000年 | 198篇 |
1999年 | 168篇 |
1998年 | 170篇 |
1997年 | 128篇 |
1996年 | 140篇 |
1995年 | 121篇 |
1994年 | 115篇 |
1993年 | 78篇 |
1992年 | 93篇 |
1991年 | 56篇 |
1990年 | 60篇 |
1989年 | 59篇 |
1988年 | 58篇 |
1987年 | 47篇 |
1986年 | 39篇 |
1985年 | 53篇 |
1984年 | 39篇 |
1983年 | 38篇 |
1982年 | 39篇 |
1981年 | 30篇 |
1980年 | 21篇 |
1979年 | 25篇 |
1978年 | 29篇 |
1977年 | 13篇 |
1976年 | 21篇 |
1975年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
《Journal of the Academy of Nutrition and Dietetics》2022,122(11):2060-2071
BackgroundVoices for Food was a longitudinal community, food pantry–based intervention informed by the social ecological model, and designed to improve food security, dietary intake, and quality among clients, which was carried out in 24 rural food pantries across 6 Midwestern states.ObjectiveOur objective was to evaluate changes in adult food security, dietary intake, and quality from baseline (2014) to follow-up (2016), and to assess the role of adult food security on dietary outcomes.DesignA multistate, longitudinal, quasi-experimental intervention with matched treatment and comparison design was used to evaluate treatment vs comparison group changes over time and changes in both groups over time.Participants/settingAdult food pantry clients (n = 617) completed a demographic food security survey, and up to three 24-hour dietary recalls at baseline (n = 590) and follow-up (n = 160).InterventionCommunity coaching served as the experimental component, which only “treatment” communities received, and a food council guide and food pantry toolkit were provided to both “treatment” and matched “comparison” communities.Main outcome measuresChange in adult food security status, mean usual intakes of nutrients and food groups, and Healthy Eating Index-2010 scores were the main outcome measures.Statistical analyses performedLinear mixed models estimated changes in outcomes by intervention group and by adult food security status over time.ResultsImprovements in adult food security score (–0.7 ± 0.3; P = .01), Healthy Eating Index-2010 total score (4.2 ± 1.1; P < .0001), and empty calories component score (3.4 ± 0.5; P <.0001) from baseline to follow-up were observed in treatment and comparison groups, but no statistically significant changes were found for adult food security status, dietary quality, and usual intakes of nutrients and food groups between the 2 groups over time. The intervention effect on dietary quality and usual intake changes over time by adult food security status were also not observed.ConclusionsFood pantry clients in treatment and comparison groups had higher food security and dietary quality at the follow-up evaluation of the Voices for Food intervention trial compared with baseline, despite the lack of difference among the groups as a result of the experimental coaching component. 相似文献
2.
3.
IntroductionEvidence for the relationship between movement behaviors and mental health among adolescents is inconclusive. We aimed to identify profiles of digital media use (including related bedtime delay) and leisure-time physical activity (LTPA) in adolescence, and to examine whether preadolescent mental health predicted later behavior profiles.MethodsThis study included 1285 participants assessed at 11 years of age, and followed-up four years later. Participants completed the Self-Perception Profile for Children (SPPC), Center for Epidemiological Studies Depression Scale for Children (CES-DC) and Screen for Child Anxiety-Related Emotional Disorders (SCARED) at baseline, and reported digital media use (active and passive use, gaming, and related bedtime delays) and LTPA at follow-up. A latent class approach was employed to identify behavior profiles, membership of which was then predicted with mental health and covariates, including baseline digital media use and LTPA.ResultsWe identified four behavior profiles: 1) high digital media use/moderate LTPA (20% of adolescents; 78% boys), 2) moderate digital media use/high LTPA (31%; 28%), 3) high digital media use/high LTPA (26%; 15%), 4) high passive digital media use and gaming/low LTPA (23%; 89%). After adjusting for covariates, higher LTPA and better perception of athletic competence at baseline associated with higher odds of belonging to any other profile than to the unhealthiest profile (4) at follow-up. Symptoms of depression or anxiety did not associate with later behavior profiles.ConclusionsLTPA and related self-esteem seem to be stronger predictors of future digital media use and LTPA behavior during adolescence than mental health symptoms alone. 相似文献
4.
5.
6.
《Pediatric clinics of North America》2015,62(6):1463-1477
7.
8.
《Allergologia et immunopathologia》2019,47(4):322-327
BackgroundChildren with IgE-mediated cow's milk allergy (IgE-CMA) with gastrointestinal symptoms tolerate yogurt at 100%. Yogurt tolerance in children with IgE-CMA with urticaria and anaphylaxis was 7%.MethodsWe enrolled children with IgE-CMA with cutaneous, respiratory, gastrointestinal and anaphylactic symptoms. All performed prick by prick (PbP) and oral food challenge (OFC) with yogurt. Some children performed also an OFC with CM mixed with wheat flour and baked, baked liquid CM, parmesan.Results34 children were enrolled, 31/34 (91%) with systemic adverse reaction after ingestion of CM (systemic CMA), 3/34 (9%) with isolated contact urticaria (ICU CMA). PbP with yogurt was negative only in one patient. OFC with yogurt was passed (that is, the OFC was negative) by 20/31 (64%) of the children with systemic CMA. 10/11 (91%) of the patients who failed OFC (that is, the OFC was positive) with yogurt were positive to SPT with casein vs. 8/20 (40%) of the patients who passed it (p = 0.018). None of the 19 children who passed OFC with yogurt failed all OFC with processed CM forms other than yogurt that tested vs. 4/8 among those who failed OFC with yogurt (p = 0.006). The rub test with yogurt was negative in 1/3 (33%) of the patients with ICU CMA.ConclusionsThe results of our study are placed alongside others already present in the literature and concerning other methods of processing CM proteins and help to reduce the dietary restrictions of the majority of children with systemic IgE-CMA. 相似文献
9.
Aditya Kelkar Caroll Webers Rohit Shetty Jai Kelkar Nikhil Labhsetwar Abhishek Pandit Madhulika Malode Sayali Tidke 《Indian journal of ophthalmology》2020,68(10):2143
Purpose:To evaluate the rate of compliance and the reasons for loss to follow-up in Indian patients with diabetic macular edema (DME), age-related macular degeneration (AMD), and retinal vein occlusion (RVO) being treated with anti-vascular endothelial growth factor (VEGF) therapy.Methods:This was a retrospective single-center study. Patients with DME, AMD, or RVO were eligible if they initiated anti-VEGF therapy between January 2013 and December 2017. Patients'' data were obtained from hospital electronic records, including the number of injections received, visits, details of follow-up, missed appointments, and reasons for loss to follow-up (>365 days).Results:A total of 648 patients were eligible for the study, of which 334 (51.54%) patients were lost to follow-up. Overall, 343 (64.96%) were males and the overall mean (SD) age was 66.40 (7.44) years. A total of 376 (58.0%) patients had a history of diabetes and 364 (56.2%) patients had a history of hypertension. Further, 127 (38.0), 112 (33.5), and 95 (28.4) had DME, AMD, and RVO, respectively and were lost to follow-up. The most commonly reported reason for loss to follow-up was “non-affordability” (n = 120; 41.1%) followed by “no improvement in vision” (n = 83; 28.4%). “No improvement in vision” (42.2%) and “non-affordability” (37.5%) were higher among patients with DME. No association was found in gender- and treatment-wise distribution of reasons for loss to follow-up.Conclusion:The results showed that around half of the patients with DME, AMD, and RVO were lost to follow-up to intravitreal anti-VEGF therapy, and the most common factors were “non-affordability” and “no improvement in vision.” 相似文献
10.