全文获取类型
收费全文 | 45360篇 |
免费 | 3265篇 |
国内免费 | 166篇 |
专业分类
耳鼻咽喉 | 517篇 |
儿科学 | 1471篇 |
妇产科学 | 757篇 |
基础医学 | 5562篇 |
口腔科学 | 632篇 |
临床医学 | 4735篇 |
内科学 | 9850篇 |
皮肤病学 | 729篇 |
神经病学 | 4261篇 |
特种医学 | 1774篇 |
外科学 | 7757篇 |
综合类 | 431篇 |
一般理论 | 82篇 |
预防医学 | 3535篇 |
眼科学 | 1265篇 |
药学 | 2397篇 |
中国医学 | 48篇 |
肿瘤学 | 2988篇 |
出版年
2023年 | 422篇 |
2022年 | 704篇 |
2021年 | 1615篇 |
2020年 | 806篇 |
2019年 | 1335篇 |
2018年 | 1617篇 |
2017年 | 1096篇 |
2016年 | 1219篇 |
2015年 | 1293篇 |
2014年 | 1815篇 |
2013年 | 2196篇 |
2012年 | 3645篇 |
2011年 | 3626篇 |
2010年 | 1991篇 |
2009年 | 1769篇 |
2008年 | 2956篇 |
2007年 | 2904篇 |
2006年 | 2796篇 |
2005年 | 2628篇 |
2004年 | 2591篇 |
2003年 | 2177篇 |
2002年 | 2001篇 |
2001年 | 356篇 |
2000年 | 287篇 |
1999年 | 335篇 |
1998年 | 397篇 |
1997年 | 341篇 |
1996年 | 268篇 |
1995年 | 260篇 |
1994年 | 206篇 |
1993年 | 189篇 |
1992年 | 230篇 |
1991年 | 217篇 |
1990年 | 196篇 |
1989年 | 164篇 |
1988年 | 144篇 |
1987年 | 170篇 |
1986年 | 122篇 |
1985年 | 163篇 |
1984年 | 150篇 |
1983年 | 154篇 |
1982年 | 144篇 |
1981年 | 118篇 |
1980年 | 102篇 |
1979年 | 111篇 |
1978年 | 86篇 |
1977年 | 67篇 |
1976年 | 50篇 |
1972年 | 55篇 |
1970年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
J Brent Richards William D Leslie Lawrence Joseph Kerry Siminoski David A Hanley Jonathan D Adachi Jacques P Brown Suzanne Morin Alexandra Papaioannou Robert G Josse Jerilynn C Prior K Shawn Davison Alan Tenenhouse David Goltzman 《Journal of bone and mineral research》2007,22(2):228-234
The impact of clinical risk factor-based absolute risk methods on the prevalence of high risk for osteoporotic fracture is unknown. We applied absolute risk methods to 6646 subjects and found that the prevalence of elderly women deemed to be at high risk increased substantially, whereas the overall prevalence was highly dependent on the threshold used to designate high risk. INTRODUCTION: Many groups have advocated using absolute risk methods that incorporate clinical risk factors to target patients for osteoporosis therapy. We examined how the application of such absolute risk classification systems influences the prevalence of those considered to be at high risk for osteoporotic fracture and compared these systems to one based solely on BMD. MATERIALS AND METHODS: Using 6646 subjects from the Canadian Multicentre Osteoporosis Study (CaMos), a prospective, randomly selected, population-based cohort, we assessed three different systems for determining prevalence of high risk for osteoporotic fracture: a BMD-based system; a simplified risk factor system incorporating age, sex, BMD, and two clinical risk factors; and a comprehensive system, incorporating age, sex, BMD, and seven clinical risk factors. The 10-year absolute risks of incident fragility fracture were compared across systems using three different high-risk thresholds. RESULTS: The prevalence of a T score < or = -2.5 was 18.8% (95% CI: 17.7-19.9%) in women and 3.9% (95% CI: 3.0-4.7%) in men. Using a 15% 10-year risk of fracture threshold, the prevalence of women at high risk increased to 46.9% (95% CI: 45.4-48.4) and 42.5% (95% CI: 41.1-43.9) when the comprehensive and simplified risk factor classification systems were used, respectively. Using a 25% 10-year absolute risk threshold, the prevalence of high risk was similar to that of the BMD-based system, whereas the 20% threshold gave intermediate rates. All thresholds analyzed resulted in an increased prevalence of older women at high risk for fracture, whereas only the 15% 10-year risk of fracture threshold resulted in an increase in the prevalence of men at high risk. CONCLUSIONS: The application of risk factor-based systems results in an increased prevalence of older women at high risk. The prevalence of individuals at high risk may increase with changes to the methods used to determine those who are eligible for therapy. These data have important implications for the pattern of care and costs of treating osteoporotic fractures. 相似文献
72.
Erinn T Rhodes Jonathan A Finkelstein Richard Marshall Carole Allen Matthew W Gillman David S Ludwig 《Ambulatory Pediatrics》2006,6(2):110-114
OBJECTIVE: The American Diabetes Association (ADA) recommends screening children at risk for type 2 diabetes with a fasting plasma glucose test or an oral glucose tolerance test. The purpose of this study was to describe attitudes, barriers, and practices related to type 2 diabetes screening in children among pediatric clinicians. METHODS: Pediatricians, nurse practitioners and physician assistants from a multispecialty, group practice in Eastern Massachusetts completed a mailed survey. To assess screening practice, three vignettes were presented representing pediatric patients with low, moderately high, and high risk for type 2 diabetes. The moderately high-risk and high-risk patients met ADA criteria for screening. ADA-consistent practice was defined as only screening the moderately high-risk and high-risk patients; lower-threshold practice was defined as also screening the low-risk patient; and higher threshold practice was screening only the high-risk patient. RESULTS: Sixty-two of 90 clinicians responded (69%). Based on intent to screen in the 3 vignettes, 21% of respondents reported ADA-consistent screening practice, 39% lower-threshold, and 35% higher-threshold screening practice. Five percent had incomplete or nonclassifiable responses. Many clinicians ordered screening tests other than those recommended by the ADA; few (< or =8% in any vignette) ordered only an ADA-recommended test. Preferences for nonfasting tests were influenced by nonmedical factors such as access to or cost of transportation. Inadequate patient education materials and unclear recommendations for appropriate screening methods were the most frequently reported moderate/strong barriers to screening. CONCLUSIONS: Most respondents reported type 2 diabetes screening practices that differed from current ADA recommendations. Our findings suggest that type 2 diabetes screening tests must be practical for clinicians and patients if they are to be used in pediatric practice. Further study of the benefits and cost-effectiveness of type 2 diabetes screening in children is warranted to clarify the role and optimal methods for screening in pediatric primary care. 相似文献
73.
Jonathan D. Moreno Ph.D. 《HEC forum》2006,18(4):368-369
74.
75.
76.
Kevin O'Brien Jean Wright Frances Conboy YeWeng Sanjie Nicky Mandall Stephen Chadwick Ivan Connolly Paul Cook David Birnie Mark Hammond Nigel Harradine David Lewis Cathy McDade Laura Mitchell Alison Murray Julian O'Neill Mike Read Stephen Robinson Dai Roberts-Harry Jonathan Sandler Ian Shaw 《American journal of orthodontics and dentofacial orthopedics》2003,124(3):234-43; quiz 339
This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion. This multicenter trial was carried out in the United Kingdom. A total of 174 children, aged 8 to 10 years old, with Class II Division 1 malocclusion were randomly allocated to receive treatment with a Twin-block appliance or to an untreated, control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in reduction of overjet, correction of molar relationships, and reduction in severity of malocclusion. Most of this correction was due to dentoalveolar change, but some was due to favorable skeletal change. Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion. The small change in the skeletal relationship might not be considered clinically significant. 相似文献
77.
Elizabeth R. Woods M.D. M.P.H. Jonathan D. Klein M.D. M.P.H. Gina M. Wingood Sc.D. M.P.H. Eve S. Rose M.S.P.H. David Wypij Ph.D. Sion Kim Harris Ph.D. Ralph J. Diclemente Ph.D. 《The Journal of adolescent health》2006,38(6):753.e1-753.e7
PurposeAlthough an adult model of patient-provider mutual exchange of information has been proposed, there is no guiding model for adolescents or measurement methodology. Our purpose was to develop a new scale of patient-provider interaction for adolescents accessing reproductive health care and at risk for sexually transmitted diseases (STDs) and human immunodeficiency virus (HIV), and assess the reliability and validity of the scale.MethodsThe Adolescent Patient-Provider Interaction Scale (APPIS) was developed from the Roter and Hall theory of doctor-patient relationships, previously validated adolescent satisfaction and communication scales, and focus group and individual elicitation interviews. To assess construct validity, the new nine-item APPIS was compared with the satisfaction scale used by the Young Adult Health Care Survey (YAHCS), and Kahn’s Provider Communication Scale. Pearson correlation coefficients were used to examine convergence across scales, and factor analysis of the APPIS was performed.ResultsThe study recruited 192 African American girls aged 17.9 ± 1.7 years (range 15–21 years) from three sites: a county STD clinic (n = 51), urban adolescent clinic (n = 99), and a family planning clinic (n = 42). Most participants (85%) rated their overall health care highly (≥ 7 on a 10-point scale); 49% felt that both the provider and patient were “in charge” of the visit, and 88% “strongly agreed” or “agreed” that there was an equal “exchange of information” during the visit. The APPIS showed good internal consistency (Cronbach alpha = .75), and moderate convergence with the six-item YAHCS scale (r = .57, p < .001) and seven-item Kahn scale (r = .48, p < .001). Three factors emerged from exploratory factor analyses, supporting our conceptualization of patient-provider interaction as being multi-dimensional.ConclusionsA new theory-based scale of adolescent patient-provider interaction compares favorably with previous scales of health care satisfaction and communication. The new APPIS may be useful for evaluating approaches to improve health care outcomes for adolescents at-risk for STDs and HIV. 相似文献
78.
Jean-Pierre Chanoine MD PhD Sarah Hampl MD FAAP Craig Jensen MD Mark Boldrin MS Jonathan Hauptman MD 李呈亿 《美国医学会杂志》2006,25(1):34-43
背景:儿童和青少年超重和肥胖正迅速增加。在该人群,单纯行为疗法减肥及维持体重下降的效果有限,但是对药物治疗尚未进行广泛的研究。
目的:确定奥利州他(Orlistat)在青少年体重治疗方面的效果及其安个性。
设计、地点和病例:于美国和加拿大32个中心、539例肥胖青少年(12—16岁;体重指数[body mass index,BMI]在第95百分化之上≥2单位)进行的多ln0、54剧(2000年8月至2002年10月)随机双盲研究。
干预:给予奥利司他(n=357)或安慰剂(n=182)120mg,每口3次,持续1年;加适度低热卡饮食(脂肪占30%)、运动和行为治疗。
主要观察指标:BMI变化;二级指标包括腰围和髋用、体重下降、脂质测量以及机体对口服葡萄糖的血糖和胰岛素反心。
结果:至12周时,两组BMI均有下降;此后,奥利司他组体重维持稳定而安慰剂组则超过基线。研究结束时,奥利司他组BMI下降0.55。而安慰剂组则增加0.31(P=0.001)。与安慰剂组的15.7%相比,奥利司他组26.5%的病例BMI下降≥5%(P=0.005);BMI下降≥10%者分别为4.5%和13.3%(P=0.002)。在研究结束时,奥利司他组体重增加0.53kg,安慰剂组增加3.14kg(P〈0.001)。双能X线吸收测量娃示,这种差异可用脂肪体再的变化解释。奥利司他组腰围下降,安慰剂组腰围上升(-1.33cm比+0.12cm;P〈0.05)。奥利司他组发生轻至中度胃肠道不良事件者为9%-50%,安慰剂组为1%~13%。
结论:与安慰剂比较,奥利司他与饮食、运动和行为改善联合可显著改善肥胖青少年体重的治疗。在这个青少年人群,连续使用奥利司他1年并无重要安全问题,尽管奥利司他组胃肠道不良事件较为常见。 相似文献
79.
80.
A literature review of autograft and allograft anterior cruciate ligament reconstruction 总被引:3,自引:0,他引:3
Jonathan Marrale Matthew C. Morrissey Fares S. Haddad 《Knee surgery, sports traumatology, arthroscopy》2007,15(6):690-704
Knee anterior cruciate ligament reconstructive surgery has significantly evolved and now includes the option of using an allograft.
This has resulted in numerous studies evaluating the advantages and disadvantages of allografts. The purpose of this literature
review is to evaluate this research and present important findings to allow the selection of the most appropriate graft source
when considering allograft versus autograft reconstruction. 相似文献