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   381篇
  免费   29篇
耳鼻咽喉   9篇
儿科学   12篇
妇产科学   14篇
基础医学   44篇
口腔科学   7篇
临床医学   40篇
内科学   21篇
皮肤病学   4篇
神经病学   39篇
特种医学   4篇
外科学   55篇
综合类   5篇
一般理论   1篇
预防医学   90篇
眼科学   8篇
药学   45篇
中国医学   1篇
肿瘤学   11篇
  2023年   3篇
  2021年   4篇
  2020年   4篇
  2019年   4篇
  2018年   7篇
  2017年   4篇
  2016年   5篇
  2015年   3篇
  2014年   11篇
  2013年   16篇
  2012年   28篇
  2011年   19篇
  2010年   11篇
  2009年   11篇
  2008年   12篇
  2007年   22篇
  2006年   17篇
  2005年   24篇
  2004年   20篇
  2003年   11篇
  2002年   19篇
  2001年   20篇
  2000年   17篇
  1999年   10篇
  1998年   6篇
  1997年   6篇
  1996年   2篇
  1995年   4篇
  1994年   3篇
  1993年   3篇
  1992年   5篇
  1991年   4篇
  1990年   4篇
  1989年   6篇
  1988年   4篇
  1987年   3篇
  1986年   7篇
  1985年   9篇
  1984年   5篇
  1983年   3篇
  1981年   3篇
  1980年   2篇
  1979年   4篇
  1976年   2篇
  1975年   2篇
  1974年   4篇
  1972年   2篇
  1970年   2篇
  1969年   2篇
  1968年   2篇
排序方式: 共有410条查询结果,搜索用时 593 毫秒
41.
Human platelet lipooxygenase converts arachidonic acid to 12-hydroperoxy-eicosatetraenoic acid (12-HPETE), which is rapidly reduced by peroxidases to 12-hydroxy-eicosatetraenoic acid (12-HETE). This study was conducted to examine the effect of vitamin E supplementation on platelet 12-lipooxygenase activity. Sixteen healthy subjects were supplemented with 400 IU/day of either D-alpha-tocopherol (268 mg) or DL-alpha-tocopherol (364 mg) for 4 wk. Supplements elicited a transitory increase of lipooxygenase activity but a suppression of peroxidase activity, as indicated by increased 12-HETE production and 12-HPETE accumulation. Plasma-tocopherol concentration was double the presupplement value and remained stable during supplementation. Neither age, sex, nor isomeric form of tocopherol supplement significantly influenced the pattern of response. Results show that vitamin E exerts a differential effect on platelet lipooxygenase and peroxidase activities.  相似文献   
42.
SCH 56592 (posaconazole), a new triazole antifungal agent, was tested in vitro, and its activity was compared to that of itraconazole against 39 Aspergillus strains and to that of fluconazole against 275 Candida and 9 Cryptococcus strains. The SCH 56592 MICs for Aspergillus ranged from 64 microg/ml. SCH 56592 showed excellent activity against Aspergillus fumigatus and Aspergillus flavus in a pulmonary mouse infection model. When administered therapeutically, the 50% protective doses (PD(50)s) of SCH 56592 ranged from 3.6 to 29.9 mg/kg of body weight, while the PD(50)s of SCH 56592 administered prophylactically ranged from 0.9 to 9.0 mg/kg; itraconazole administered prophylactically was ineffective (PD(50)s, >75 mg/kg). SCH 56592 was also very efficacious against fluconazole-susceptible, -susceptible dose-dependent, or -resistant Candida albicans strains in immunocompetent or immunocompromised mouse models of systemic infection. The PD(50)s of SCH 56592 administered therapeutically ranged from 0.04 to 15.6 mg/kg, while the PD(50)s of SCH 56592 administered prophylactically ranged from 1.5 to 19.4 mg/kg. SCH 56592 has excellent potential for therapy against serious Aspergillus or Candida infections.  相似文献   
43.
Oxacillin-Induced Lysis of Staphylococcus aureus   总被引:3,自引:0,他引:3       下载免费PDF全文
Six clinical isolates of Staphylococcus aureus were compared for their relative susceptibilities to the killing effects of oxacillin. Three of the strains had minimum bactericidal concentrations which were >10 times the minimum bacteriostatic concentration for this antibiotic and were designated tolerant (Tol(+)). The other strains had minimum bactericidal concentrations which were comparable to the minimum bacteriostatic concentration (Tol(-)). Lysis curves of these strains revealed that the Tol(+) strains exhibited a diminished rate of lysis when inhibited by oxacillin. This reduced rate of lysis was reflected also in a reduced rate of viability loss when the cells were exposed to oxacillin. During log growth the uptake of [(14)C]glycerol by Tol(+) cells was 1.5-fold greater than that by Tol(-) cells. Glycerol-labeled cells of each phenotype secreted radioactivity when inhibited by oxacillin. However, the Tol(+) strains released over twice as much label as the Tol(-) strains. No difference in the proportion of lipid secreted by the two phenotypes was found. The behavior of 60 to 65% of the labeled material released by inhibited cells during both sodium dodecyl sulfate gel electrophoresis and Sepharose 6B chromatography corresponded to that of lipoteichoic acid. When the major component of secreted material was added to oxacillin-inhibited Tol(-) strains, an inhibition of the lytic response was observed. These results suggest that oxacillin tolerance in S. aureus could be related to the enhanced secretion of an autolysin inhibitor, such as lipoteichoic acid.  相似文献   
44.

Introduction

Little evidence exists evaluating the possible effect of dressings on the recovery of function, sensation and joint motion following a hand burn. Hand burns are traditionally covered by a layer of non-adherent dressing followed by gauze and bandages. However, there is no evidence for the efficacy of this type of coverage relative to a functional recovery. The Gore-tex bag has a small body of research supporting its ability to provide a superior healing atmosphere, however there is no literature directly comparing it with the traditional dressing.

Method

A randomised cross-over design was implemented to compare Gore-tex bags and traditional dressings in 30 healthy volunteers. Seven outcome measures of function, sensation, joint range of movement and subject perceptions were recorded before dressing, during both Gore-tex and traditional dressing interventions and between dressings.

Results

Statistically significant differences were found between the traditional dressings and Gore-tex bags. The Gore-tex bag dressings proved better for digit range of motion, 1st CMC joint motion and sensation. The traditional dressings were significantly better when perceived comfort was tested and there was no significant difference between the traditional dressing and Gore-tex bag regarding function and perceived function.

Conclusion

The results of this study suggest that traditional dressings may detrimentally affect movement and reduce sensation but not necessarily affect function or comfort. Further investigation in a patient cohort with burnt hands is recommended.  相似文献   
45.
There have been widespread changes in society and the roles of professionals. This change is also reflected in health care, where there is now acceptance of the need to involve patients in decision making. In prescribing specifically, the concordance agenda was developed alongside these initiatives to encourage improved medication taking and reduce wastage. However the extent to which these partnerships are delivered in practice remains unclear. This paper explores some of the issues to be considered when preparing patients and professionals for partnership and summarizes the limited evidence of barriers to, and benefits of, this approach. Firstly patients must be given the confidence, skills and knowledge to be partners. They need information about medicines, provided in ways known to be acceptable to them. Likewise professionals may need new skills to be partners. They need to understand the patient agenda and may need training and support to change the ways in which they consult with patients. There are also practical issues such as the perceived increase in time taken when consulting in partnership mode, room layout, computer interfaces and record keeping. Health care professionals other than doctors are also expected to behave in partnership mode, whether this is as prescribers in their own right or in supporting the prescribing of others. Whilst much has been claimed for the benefit of partnership approaches, hard evidence is limited. However whilst there is still much more to understand there will be no going back to the paternalistic model of the mid 20th century.  相似文献   
46.
47.
OBJECTIVE: The primary goal was to evaluate sex differences in child weight control programs that targeted increasing physical activity (increase) or the combination of reducing sedentary behavior and increasing physical activity (combined). A second goal was to evaluate the benefits of family-based interventions on nontargeted siblings. RESEARCH METHODS AND PROCEDURES: Sixty-seven families with obese children and 89 siblings were randomized to interventions that targeted increasing physical activity (increase) or the combination of reducing sedentary behavior and increasing physical activity (combined). Targeted participants and nontargeted siblings were followed for 1 year. RESULTS: At 12 months, boys showed significantly better percentages of overweight changes (-15.8%) for the combined treatment than girls (-1.0%), with no significant differences for the increase intervention for boys (-9.3%) or girls (-7.6%). Boys adhered to treatment better than girls (p < 0.01). Adherence and predilection for physical activity were significant predictors of targeted child weight loss at 1 year in multiple regression analysis. Predictors of sibling weight loss included age, number of siblings, targeted child percentage of overweight change, and the interaction of group assignment by same sex of treated sibling. DISCUSSION: Gender may influence response to programs that attempt to decrease sedentary behavior, and generalization of treatment effects to siblings may depend on the intervention and characteristics of the siblings.  相似文献   
48.
Medication review of patients on long-term treatment in general practice in the UK has been reported to be inadequate. Proposals followed suggesting that pharmacists could use their expertise to lead such a medication review in conjunction with the general practitioner. This paper describes the concept of clinical medication review by a pharmacist based in general practice. We describe the development of a method for a structured and systematic process for undertaking such a review in clinics conducted by a pharmacist. The method was developed for a nationally funded study in the UK. We provide a definition of clinical medication review and suggests a structure for the process through data gathering, evaluation and implementation.  相似文献   
49.

Background

If guidelines regarding recommended activity levels for young people are to be meaningful and comparable, it should be clear how they are operationalised. It is usually open to interpretation whether young people are required to meet activity and screen time targets (1) all days of the week, (2) on most days of the week, (3) on average across all days, or (4) whether compliance should be understood as the probability that a randomly selected young person meets the guidelines on a randomly selected day. This paper studies this question using data drawn from the Australian Health of Young Victorians study.

Methods

The subjects for this study were 885 13–19 year olds who recalled four days of activities using a computerised use-of-time instrument, the Multimedia Activity Recall for Children and Adolescents (MARCA). Daily minutes of moderate-to-vigorous physical activity (MVPA) and screen time were calculated. The prevalence of compliance to Australian guidelines (≥ 60 min/day of MVPA and ≤ 120 min/day of screen time outside of school hours) was calculated using the four methods.

Results

The four methods resulted in significantly different prevalence estimates for compliance to the MVPA guideline (20–68%), screen guideline (12–42%) and both guidelines (2–26%). Furthermore, different individuals were identified as compliant by the different methods.

Conclusion

Clarification of how compliance to guidelines should be operationalised would assist in comparisons between studies, and in consistency in determining correlates of compliance.  相似文献   
50.
BACKGROUND: Circulating endothelial progenitor cells (EPCs) play a role in the repair and regeneration of the endothelium and may represent a novel cardiovascular risk factor. South Asian subjects have an increased risk of cardiovascular disease which is not fully explained by known risk factors. This study examined associations of EPCs with atherosclerosis and possible ethnic differences in EPCs. MATERIALS AND METHODS: A population sample of 58 European and South Asian adult men was enriched with the recruitment of an additional 59 European and South Asian men with known coronary disease. The coronary artery calcification score was measured by multi-slice computerized tomography (CT), carotid and femoral intima-media thickness (IMT), and femoral plaques were measured by ultrasound. The subjects were further subdivided into three categories of coronary artery disease on the basis of coronary artery calcification score and clinical history. Total EPCs and non-senescent EPCs (ns-EPCs) were quantified after 5 days cell culture and the number of late outgrowth colonies was measured over a 6-week test period. Circulating CD34+ haematopoietic precursor cells were measured by flow cytometry. RESULTS: Individuals with femoral plaques had reduced total and ns-EPCs. The number of ns-EPCs were reduced in individuals with the most coronary atheroma and were inversely related to the coronary calcification score and femoral IMT. These relationships persisted after multivariate adjustment for other risk factors. The numbers of late outgrowth colonies or circulating CD34+ cells were unrelated to the presence of atherosclerosis. There were no differences in the number of EPCs between European and South Asian subjects. CONCLUSION: The number of EPCs are reduced in subjects with atherosclerosis independent of other risk factors. Reduction in EPC numbers may be an independent risk factor for atherosclerosis but does not explain ethnic differences in cardiovascular risk.  相似文献   
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