全文获取类型
收费全文 | 1209篇 |
免费 | 58篇 |
国内免费 | 149篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 60篇 |
妇产科学 | 6篇 |
基础医学 | 96篇 |
口腔科学 | 20篇 |
临床医学 | 190篇 |
内科学 | 328篇 |
皮肤病学 | 30篇 |
神经病学 | 26篇 |
特种医学 | 315篇 |
外科学 | 61篇 |
综合类 | 28篇 |
预防医学 | 51篇 |
眼科学 | 31篇 |
药学 | 114篇 |
1篇 | |
肿瘤学 | 57篇 |
出版年
2021年 | 7篇 |
2019年 | 9篇 |
2018年 | 18篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 17篇 |
2014年 | 23篇 |
2013年 | 34篇 |
2012年 | 17篇 |
2011年 | 20篇 |
2010年 | 39篇 |
2009年 | 42篇 |
2008年 | 31篇 |
2007年 | 111篇 |
2006年 | 28篇 |
2005年 | 32篇 |
2004年 | 17篇 |
2003年 | 7篇 |
2002年 | 21篇 |
2001年 | 22篇 |
2000年 | 13篇 |
1999年 | 18篇 |
1998年 | 78篇 |
1997年 | 76篇 |
1996年 | 71篇 |
1995年 | 61篇 |
1994年 | 42篇 |
1993年 | 53篇 |
1992年 | 10篇 |
1991年 | 16篇 |
1990年 | 14篇 |
1989年 | 56篇 |
1988年 | 35篇 |
1987年 | 33篇 |
1986年 | 30篇 |
1985年 | 34篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 28篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 19篇 |
1976年 | 31篇 |
1975年 | 18篇 |
1974年 | 7篇 |
1973年 | 7篇 |
1972年 | 10篇 |
1971年 | 8篇 |
排序方式: 共有1416条查询结果,搜索用时 15 毫秒
51.
目的:观察白藜芦醇对一次性力竭游泳大鼠肝脏组织的作用及发挥作用的最佳口服剂量。方法:实验于2006-05/07在成都体育学院运动医学系动物实验室完成。①实验分组:选取雄性SD大鼠70只,随机分为7组,每组10只,分别为安静对照组,运动对照组,运动 15mg/kg白藜芦醇组,运动 50mg/kg白藜芦醇组,运动 100mg/kg白藜芦醇组,运动 200mg/kg白藜芦醇组,运动 300mg/kg白藜芦醇组。②实验干预:不同剂量白藜芦醇组每天灌胃15,50,100,200,300mg/kg白藜芦醇,安静对照组和运动对照组分别灌胃相同体积的溶媒(二甲亚砜 生理盐水),连续5周。末次给予实验用样品1h后,各运动组每只鼠尾跟部负荷3%体质量铅皮,置于水深50cm、水温(31±1)℃游泳槽中游泳。游泳力竭后即刻,股动脉取血并迅速取出肝组织。③指标检测:赖氏比色法测定血清中谷丙转氨酶活性;邻苯三酚自氧化法测定肝组织超氧化物歧化酶活性;硫代巴比妥酸法测定肝组织丙二醛含量。结果:纳入动物70只,均进入结果分析。①血清谷丙转氨酶活性和肝组织中丙二醛含量:运动对照组显著高于安静对照组,不同剂量白藜芦醇组低于运动对照组(P<0.05或P<0.01)。运动 100,200,300mg/kg白藜芦醇组低于运动 15,50mg/kg白藜芦醇组[谷丙转氨酶活性:(972.36±121.86),(944.36±105.35),(888.34±88.68),(1773.52±89.35),(1377.78±27.01)nkat/L,P<0.01;丙二醛含量:(7.90±2.56),(7.69±3.69),(7.13±2.62),(19.90±2.21),(12.16±1.78)μmol/g,P<0.05]。100,200,300mg/kg白藜芦醇组间差异无显著性。②肝脏组织中超氧化物歧化酶活性:运动对照组显著低于安静对照组,不同剂量白藜芦醇组高于运动对照组(P<0.05或P<0.01)。运动 100,200,300mg/kg白藜芦醇组高于15,50mg/kg白藜芦醇组[(2325.80±163.37),(2379.14±121.86),(2447.16±89.18),(1096.05±120.19),(1514.64±28.17)μkat/g,P<0.01]。结论:①白藜芦醇对力竭性运动大鼠肝脏组织具有保护作用。②100,200,300mg/kg白藜芦醇对肝脏组织发挥保护作用效果优于15,50mg/kg,建议使用100mg/kg白藜芦醇就能达到理想效果。 相似文献
52.
53.
54.
55.
56.
Background
Whole body vibration (WBV) exposure at work is common and studies found evidence that this exposure might cause low back pain (LBP). A recent review concluded there is a lack of evidence of effective strategies to reduce WBV exposure. Most research in this field is focussed on the technical implications, although changing behaviour towards WBV exposure might be promising as well. Therefore, we developed an intervention programme to reduce WBV exposure in a population of drivers with the emphasis on a change in behaviour of driver and employer. The hypothesis is that an effective reduction in WBV exposure, in time, will lead to a reduction in LBP as WBV exposure is a proxy for an increased risk of LBP. 相似文献57.
Outpatient therapy with low molecular weight heparin for the treatment of venous thromboembolism: a review of efficacy,safety, and costs 总被引:1,自引:0,他引:1
Segal JB Bolger DT Jenckes MW Krishnan JA Streiff MB Eng J Tamariz LJ Bass EB 《The American journal of medicine》2003,115(4):298-308
PURPOSE: To summarize the evidence comparing the efficacy, safety, and costs of outpatient and inpatient treatment of venous thromboembolism. METHODS: We searched the literature through March 2002 for studies comparing outpatient and inpatient treatment of venous thromboembolism with low molecular weight heparin or unfractionated heparin, and for studies addressing the costs of low molecular weight heparin use in any setting. We included studies with comparison groups or decision analyses. RESULTS: Eight studies (three randomized trials and five cohort studies) compared outpatient use of low molecular weight heparin with inpatient use of unfractionated heparin in 3762 patients. The incidence of recurrent deep venous thrombosis was similar in the two groups (median, 4% [range, 0% to 7%] vs. 6% [range, 0% to 9%]), as was major bleeding (median, 0.5% [range, 0% to 2%] vs. 1% [range, 0% to 2%]). Use of low molecular weight heparin was associated with shorter hospitalization (median, 2.7 days [range, 0.03 to 5.1 days] vs. 6.5 days [range, 4 to 9.6 days]) and lower costs (median difference, 1600 dollars). Comparisons of outpatient and in-hospital use of low molecular weight heparin reported no difference in outcomes, but there were savings in hospitalization costs. Low molecular weight heparin was also found to be more cost saving and cost-effective than unfractionated heparin, with savings of 0% to 64% (median, 57%). CONCLUSION: The evidence indicates that outpatient treatment of deep venous thrombosis with low molecular weight heparin is likely to be efficacious, safe, and cost-effective. 相似文献
58.
Clinical effectiveness research in managed-care systems: lessons from the Pediatric Asthma Care PORT. Patient Outcomes Research Team
下载免费PDF全文
![点击此处可从《Health services research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Finkelstein JA Lozano P Streiff KA Arduino KE Sisk CA Wagner EH Weiss KB Inui TS 《Health services research》2002,37(3):775-789
OBJECTIVE: To highlight the unique challenges of evaluative research on practice behavior change in the "real world" settings of contemporary managed-care organizations, using the experience of the Pediatric Asthma Care PORT (Patient Outcomes Research Team). STUDY SETTING: The Pediatric Asthma Care PORT is a five-year initiative funded by the Agency for Healthcare Research and Quality to study strategies for asthma care improvement in three managed-care plans in Chicago, Seattle, and Boston. At its core is a randomized trial of two care improvement strategies compared with usual care: (1) a targeted physician education program using practice based Peer Leaders (PL) as change agents, (2) adding to the PL intervention a "Planned Asthma Care Intervention" incorporating joint "asthma check-tips" by nurse-physician teams. During the trial, each of the participating organizations viewed asthma care improvement as an immediate priority and had their own corporate improvement programs underway. DATA COLLECTION: Investigators at each health plan described the organizational and implementation challenges in conducting the PAC PORT randomized trial. These experiences were reviewed for common themes and "lessons" that might be useful to investigators planning interventional research in similar care-delivery settings. CONCLUSIONS: Randomized trials in "real world" settings represent the most robust design available to test care improvement strategies. In complex, rapidly changing managed-care organizations, blinding is not feasible, corporate initiatives may complicate implementation, and the assumption that a "usual care" arm will be static is highly likely to be mistaken. Investigators must be prepared to use innovative strategies to maintain the integrity of the study design, including: continuous improvement within the intervention arms, comanagement by researchers and health plan managers of condition-related quality improvement initiatives, procedures for avoiding respondent burden in health plan enrollees, and anticipation and minimization of risks from experimental arm contamination and major organizational change. With attention to these delivery system issues, as well as the usual design features of randomized trials, we believe managed-care organizations can serve as important laboratories to test care improvement strategies. 相似文献
59.
Peripheral blood count abnormalities among patients with hepatitis C in the United States 总被引:1,自引:0,他引:1
An estimated 2.7 million people in the United States are infected with the hepatitis C virus (HCV), yet the influence of HCV infection on the peripheral blood count remains unknown. To investigate the prevalence of low peripheral blood counts among HCV-infected adults in the United States general population, we analyzed data collected in the third National Health and Nutrition Examination Survey (NHANES III). The study population consisted of 16,196 individuals age 18 or older who had peripheral blood counts and data on HCV infection. The lowest fifth percentile of each component of the peripheral blood was designated a priori as being low. HCV infection was assessed by antibody reactivity. HCV antibody-positive individuals were 3-fold more likely to have low neutrophil counts (HCV positive, 9% vs. HCV negative, 3%, P <.0001) and 2.6-fold more likely to have low platelet counts (HCV positive, 13% vs. HCV negative, 5%, P <.0001) independent of other evaluated factors. HCV infection was observed in more than 20% of persons with neutrophil counts below 1.0 x 10(9)/L or platelet counts less than 100 x 10(9)/L. No association was detected between anti-HCV status and anemia or other peripheral blood cell components. In conclusion, HCV-infected persons in the general population of the United States are more likely to have low neutrophil and platelet counts, and HCV testing should be considered for persons with unexplained neutrophil counts below 1.0 x 10(9)/L or platelet counts less than 100 x 10(9)/L. Alternate causes of anemia should be considered for HCV-infected persons with low red blood cell counts. 相似文献
60.
JH CHUNG 《中国药理学与毒理学杂志》2006,20(3)
Arsenic in drinking water is a worldwide health problem that is associated with cardiovascular disease, but the cause is currently unknown. In order to examine whether arsenic affects vasomotor tone in blood vessels, we investigated the effect of arsenic on agonist-induced vasorelaxation and vasoconstriction using the isolated rat aortic rings in in vitro organ bath system. 相似文献