全文获取类型
收费全文 | 300217篇 |
免费 | 42230篇 |
国内免费 | 2912篇 |
专业分类
耳鼻咽喉 | 6733篇 |
儿科学 | 8986篇 |
妇产科学 | 4905篇 |
基础医学 | 23695篇 |
口腔科学 | 4796篇 |
临床医学 | 41294篇 |
内科学 | 78243篇 |
皮肤病学 | 10507篇 |
神经病学 | 28607篇 |
特种医学 | 12987篇 |
外国民族医学 | 14篇 |
外科学 | 64430篇 |
综合类 | 2172篇 |
现状与发展 | 72篇 |
一般理论 | 109篇 |
预防医学 | 18375篇 |
眼科学 | 6474篇 |
药学 | 10911篇 |
中国医学 | 244篇 |
肿瘤学 | 21805篇 |
出版年
2023年 | 5410篇 |
2022年 | 2291篇 |
2021年 | 6231篇 |
2020年 | 7817篇 |
2019年 | 5136篇 |
2018年 | 10655篇 |
2017年 | 9792篇 |
2016年 | 11209篇 |
2015年 | 11648篇 |
2014年 | 20028篇 |
2013年 | 21885篇 |
2012年 | 15451篇 |
2011年 | 16132篇 |
2010年 | 16217篇 |
2009年 | 19622篇 |
2008年 | 15203篇 |
2007年 | 13928篇 |
2006年 | 16228篇 |
2005年 | 13635篇 |
2004年 | 12081篇 |
2003年 | 10445篇 |
2002年 | 10140篇 |
2001年 | 5792篇 |
2000年 | 4724篇 |
1999年 | 5186篇 |
1998年 | 5422篇 |
1997年 | 4874篇 |
1996年 | 4542篇 |
1995年 | 4334篇 |
1994年 | 2986篇 |
1993年 | 2513篇 |
1992年 | 2599篇 |
1991年 | 2525篇 |
1990年 | 2049篇 |
1989年 | 2104篇 |
1988年 | 1886篇 |
1987年 | 1704篇 |
1986年 | 1735篇 |
1985年 | 1550篇 |
1984年 | 1458篇 |
1983年 | 1289篇 |
1982年 | 1450篇 |
1981年 | 1248篇 |
1980年 | 1072篇 |
1979年 | 955篇 |
1978年 | 964篇 |
1977年 | 915篇 |
1976年 | 735篇 |
1975年 | 697篇 |
1974年 | 729篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Philip Peng FRCPC Manon Choiniere PhD Dominique Dion MD MSc Howard Intrater FRCPC Sandra LeFort PhD Mary Lynch FRCPC May Ong FRCPC Saifee Rashiq MSc DA FRCPC Gregg Tkachuk PhD Yves Veillette FRCPC 《Journal canadien d'anesthésie》2007,54(12):977-984
PURPOSE: The objective of this survey was to examine the services offered by multidisciplinary pain treatment facilities (MPTFs) across Canada and to compare access to care at these MPTFs. METHODS: A MPTF was defined as a clinic that advertised specialized multidisciplinary services for the diagnosis and management of patients with chronic pain, having a minimum of three different health care disciplines (including at least one medical speciality) available and integrated within the facility. The search method included approaching all hospital and rehabilitation centre administrators in Canada, the Insurance Bureau of Canada, the Workplace Safety and Insurance Board or similar body in each province. Designated investigators were responsible for confirming and supplementing MPTFs from the preliminary list for each province. Administrative leads at each eligible MPTF were asked to complete a detailed questionnaire regarding their MPTF infrastructure, clinical, research, teaching and administrative activities. RESULTS: Completed survey forms were received from 102 MPTFs (response rate 85%) with 80% concentrated in major cities, and none in Prince Edward Island and the Territories. The MPTFs offer a wide variety of treatments including non-pharmacological modalities such as interventional, physical and psychological therapy. The median wait time for a first appointment in public MPTFs is six months, which is approximately 12 times longer than non-public MPTFs. Eighteen pain fellowship programs exist in Canadian MPTFs and 64% engage in some form of research activities CONCLUSION: Canadian MPTFs are unable to meet clinical demands of patients suffering from chronic pain, both in terms of regional accessibility and reasonable wait time for patients' first appointment. 相似文献
993.
994.
996.
997.
998.
999.
1000.
Michelle K Nurzenski N Kathryn Briffa Roger I Price Benjamin C C Khoo Amanda Devine Thomas J Beck Richard L Prince 《Journal of bone and mineral research》2007,22(3):416-424
A population-based study on 1008 postmenopausal women identified that the 24% of women achieving high levels of PA and CI had 3.4-4.4% higher femoral bone strength in axial compression and 1.7-5.2% in bending than those achieving low levels, indicating that lifestyle factors influence bone strength in the proximal femur. INTRODUCTION: Extensive research has shown that increased physical activity (PA) and calcium intake (CI) decrease the rate of bone loss; however, there is little research on how these lifestyle variables affect bone geometry. This study was designed to investigate the effects of modifiable lifestyle variables, habitual PA and dietary CI, on femoral geometry in older women. MATERIALS AND METHODS: Femoral geometry, habitual PA, and dietary CI were measured in a population-based sample of 1008 women (median age+/-interquartile range, 75+/-4years) enrolled in a randomized controlled trial (RCT) of calcium supplementation. Baseline PA and CI were assessed by validated questionnaires, and 1-year DXA scans (Hologic 4500A) were analyzed using the hip structural analysis technique. Section modulus (Z), an index of bending strength, cross-sectional area (CSA), an index of axial compression strength, subperiosteal width (SPW), and centroid position, the position of the center of mass, were measured at the femoral neck (NN), intertrochanter (IT), and femoral shaft (FS) sites. These data were divided into tertiles of PA and CI, and the results were compared using analysis of covariance (ANCOVA), with corrections for age, height, weight, and treatment (calcium/placebo). RESULTS AND CONCLUSIONS: PA showed a significant dose-response effect on CSA all hip sites (p<0.03) and Z at the narrow neck and intertrochanter sites (p<0.02). For CI, there was a dose-response effect for centroid position at the intertrochanter (p=0.03). These effects were additive, such that the women (n=240) with PA in excess of 65.5 kcal/day and CI in excess of 1039 mg/day had significantly greater CSA (NN, 4.4%; IT, 4.3%; FS, 3.4%) and Z (NN, 3.9%; IT, 5.2%). These data show a favorable association between PA and aspects of bone structural geometry consistent with better bone strength. Association between CI and bone structure was only evident in 1 of 15 variables tested. However, there was evidence that there may be additive effects, whereby women with high levels of PA and CI in excess of 1039 mg/day had significantly greater CSA (NN, 0.4%; FS, 2.1%) and Z (IT, 3.0%) than women with high PA but low CI. These data show that current public health guidelines for PA and dietary CI are not inappropriate where bone structure is the health component of interest. 相似文献