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   1019篇
  免费   57篇
  国内免费   2篇
耳鼻咽喉   3篇
儿科学   16篇
妇产科学   20篇
基础医学   97篇
口腔科学   4篇
临床医学   149篇
内科学   115篇
皮肤病学   4篇
神经病学   85篇
特种医学   13篇
外科学   233篇
综合类   9篇
一般理论   1篇
预防医学   114篇
眼科学   1篇
药学   121篇
中国医学   1篇
肿瘤学   92篇
  2023年   6篇
  2022年   6篇
  2021年   22篇
  2020年   14篇
  2019年   23篇
  2018年   30篇
  2017年   17篇
  2016年   19篇
  2015年   27篇
  2014年   61篇
  2013年   77篇
  2012年   122篇
  2011年   104篇
  2010年   49篇
  2009年   33篇
  2008年   54篇
  2007年   69篇
  2006年   41篇
  2005年   40篇
  2004年   41篇
  2003年   26篇
  2002年   51篇
  2001年   3篇
  2000年   4篇
  1999年   8篇
  1998年   8篇
  1997年   9篇
  1996年   7篇
  1995年   5篇
  1994年   6篇
  1993年   2篇
  1992年   6篇
  1991年   6篇
  1990年   2篇
  1989年   7篇
  1988年   6篇
  1986年   7篇
  1985年   4篇
  1984年   10篇
  1983年   6篇
  1982年   10篇
  1981年   6篇
  1980年   4篇
  1979年   3篇
  1977年   3篇
  1976年   3篇
  1971年   2篇
  1963年   1篇
  1954年   1篇
  1947年   1篇
排序方式: 共有1078条查询结果,搜索用时 0 毫秒
41.
This study evaluated the long-term effects of a therapeutic workplace social business on drug abstinence and employment. Pregnant and postpartum women (N = 40) enrolled in methadone treatment were randomly assigned to a therapeutic workplace or usual care control group. Therapeutic workplace participants could work weekdays in training and then as employees of a social business, but were required to provide drug-free urine samples to work and maintain maximum pay. Three-year outcomes were reported previously. This paper reports 4- to 8-year outcomes. During year 4 when the business was open, therapeutic workplace participants provided significantly more cocaine- and opiate-negative urine samples than controls; reported more days employed, higher employment income, and less money spent on drugs. During the 3 years after the business closed, therapeutic workplace participants only reported higher income than controls. A therapeutic workplace social business can maintain long-term abstinence and employment, but additional intervention may be required to sustain effects.  相似文献   
42.
43.
Objectives: In 2011, the U.S. Environmental Protection Agency initiated the NexGen project to develop a new paradigm for the next generation of risk science.Methods: The NexGen framework was built on three cornerstones: the availability of new data on toxicity pathways made possible by fundamental advances in basic biology and toxicological science, the incorporation of a population health perspective that recognizes that most adverse health outcomes involve multiple determinants, and a renewed focus on new risk assessment methodologies designed to better inform risk management decision making.Results: The NexGen framework has three phases. Phase I (objectives) focuses on problem formulation and scoping, taking into account the risk context and the range of available risk management decision-making options. Phase II (risk assessment) seeks to identify critical toxicity pathway perturbations using new toxicity testing tools and technologies, and to better characterize risks and uncertainties using advanced risk assessment methodologies. Phase III (risk management) involves the development of evidence-based population health risk management strategies of a regulatory, economic, advisory, community-based, or technological nature, using sound principles of risk management decision making.Conclusions: Analysis of a series of case study prototypes indicated that many aspects of the NexGen framework are already beginning to be adopted in practice.Citation: Krewski D, Westphal M, Andersen ME, Paoli GM, Chiu WA, Al-Zoughool M, Croteau MC, Burgoon LD, Cote I. 2014. A framework for the next generation of risk science. Environ Health Perspect 122:796–805; http://dx.doi.org/10.1289/ehp.1307260  相似文献   
44.
Objectives. We examined socioeconomic disparities in tobacco dependence treatment outcomes from a free, proactive telephone counseling quitline.Methods. We delivered cognitive–behavioral treatment and nicotine patches to 6626 smokers and examined socioeconomic differences in demographic, clinical, environmental, and treatment use factors. We used logistic regressions and generalized estimating equations (GEE) to model abstinence and account for socioeconomic differences in the models.Results. The odds of achieving long-term abstinence differed by socioeconomic status (SES). In the GEE model, the odds of abstinence for the highest SES participants were 1.75 times those of the lowest SES participants. Logistic regression models revealed no treatment outcome disparity at the end of treatment, but significant disparities 3 and 6 months after treatment.Conclusions. Although quitlines often increase access to treatment for some lower SES smokers, significant socioeconomic disparities in treatment outcomes raise questions about whether current approaches are contributing to tobacco-related socioeconomic health disparities. Strategies to improve treatment outcomes for lower SES smokers might include novel methods to address multiple factors associated with socioeconomic disparities.In the United States, the prevalence of daily smoking among lower socioeconomic status (SES) groups is 3 to 4 times higher than that of higher SES groups and a leading contributor to socioeconomic health disparities.1–5 Comprehensive tobacco control programs can reduce these disparities by providing all smokers with effective treatment for tobacco dependence; however, significant socioeconomic disparities in treatment outcomes are observed in many treatment settings, raising concerns about contributing to or at least maintaining existing disparities with these approaches.6–14 Treatment delivered through telephone quitlines has become widely available in the United States and the United Kingdom.15 Proactive quitlines attract a large proportion of lower SES smokers16–18 and smokers with different demographic and clinical characteristics than in-person, community-based treatments.16,19,20 Because of their ubiquitous nature and because they appear to be especially accessible and attractive to lower SES smokers,16,17,18 quitlines have the potential to attenuate tobacco-related disparities; however, if quitlines also demonstrate socioeconomic disparities in treatment outcomes, then this would strengthen concerns about current approaches contributing to or maintaining these disparities.SES ideally incorporates the social and economic factors that influence what position individuals or groups hold in a societal structure.21,22 In health research, SES is a broad construct describing relative access to basic resources required to achieve or maintain good health.23,24 Consistent with leading conceptual models of health disparities,23–26 SES is empirically related to smoking cessation through complex reciprocal relations among clinical, environmental, and treatment utilization factors including stress, coping resources, psychological factors, exposure to other smokers, and use of treatment resources.6,27–32Cognitive–behavioral treatment (CBT) provided through proactive quitlines is a practical innovation that attracts a promising number of lower SES smokers.15–17,33 Although not targeted to or tailored for lower SES groups, CBT, when delivered appropriately, addresses individuals’ treatment-related clinical characteristics (e.g., stress, coping, dependence level, motivation, self-efficacy, environmental challenges). Nonetheless, significant disparities have been found in CBT treatment outcomes in many tobacco treatment settings.6–14 Quitlines treat smokers with different characteristics than in-person treatment,16,19,20 however, and thus might not demonstrate the same disparities as in-person CBT treatment.6–13We investigated socioeconomic disparities in tobacco dependence treatment outcomes using data from a proactive quitline in Arkansas in operation from 2005 to 2008. We used statistical modeling of abstinence at the end of treatment (EOT) and 3 and 6 months after treatment to examine the independent contribution of SES to treatment outcomes controlling for other factors. Consistent with findings from community-based treatment, we hypothesized that after accounting for demographic, clinical, environmental, and treatment utilization factors, the lowest SES participants would be least likely to achieve long-term abstinence.  相似文献   
45.

Background

Excess body weight is a risk factor for obstructive sleep apnoea (OSA). The aim of the systematic review was to establish whether weight loss via lifestyle interventions such as diet and exercise are useful in the treatment of OSA.

Methods

A literature search was conducted between 1980 and February 2012. Systematic reviews and randomised controlled trials (RCTs) with participants who had OSA, were overweight or obese, and who had undergone lifestyle interventions with the aim of improving sleep apnoea were included. Meta analyses were conducted for a subset of RCTs with appropriate data.

Results

Two systematic reviews and eight RCTs were included. Meta-analyses were conducted for four RCTs comparing intensive lifestyle interventions to a control. The overall weighted mean differences for weight change, change in apnoea -hypopnoea index (AHI) and change in oxygen desaturation index of ≥4% were as follows: −13.76 kg (95% confidence interval (CI) −19.21, −-8.32), −16.09 (95% CI −25.64, −6.54) and −14.18 (95% CI −24.23, −4.13), respectively. Although high heterogeneity within the meta analyses, all studies favoured the interventions. Long-term follow-up data from three RCTs suggest that improvements in weight and AHI are maintained for up to 60 months.

Conclusions

Intensive lifestyle interventions are effective in the treatment of OSA, resulting in significant weight loss and a reduction in sleep apnoea severity. Weight loss via intensive lifestyle interventions could be encouraged as a treatment for mild to moderate OSA.  相似文献   
46.
47.
Using cultured human osteoblast-like cells, we studied the effects of tumor necrosis factor (TNF) and recombinant human γ-interferon (γ-IFN) on osteoblast growth and function, and demonstrated that TNF stimulated bone cell proliferation and prostaglandin production while inhibiting 1,25-(OH)2D3—stimulated alkaline phosphatase activity and osteocalcin release. In contrast, γ-IFN inhibited proliferation and stimulated alkaline phosphatase activity of the cells, while inhibiting 1,25-(OH)2D3—stimulated osteocalcin production and having variable effects on the release of prostaglandins, depending on the presence of other factors. Our results suggest that TNF and γ-IFN can act directly on bone-forming cells to affect both their proliferation and their differentiated function, and that changes in the ability of cells to produce these factors in disease states may contribute to alterations in the integrity of connective tissue matrices.  相似文献   
48.
49.
In this case study, we describe a method that has potential to provide systematic support for public health information management. Public health agencies depend on specialized information that travels throughout an organization via communication networks among employees. Interactions that occur within these networks are poorly understood and are generally unmanaged. We applied organizational network analysis, a method for studying communication networks, to assess the method's utility to support decision making for public health managers, and to determine what links existed between information use and agency processes. Data on communication links among a health department's staff was obtained via survey with a 93% response rate, and analyzed using Organizational Risk Analyzer (ORA) software. The findings described the structure of information flow in the department's communication networks. The analysis succeeded in providing insights into organizational processes which informed public health managers' strategies to address problems and to take advantage of network strengths.  相似文献   
50.
Metabolic adaptation is considered an emerging hallmark of cancer, whereby cancer cells exhibit high rates of glucose consumption with consequent lactate production. To ensure rapid efflux of lactate, most cancer cells express high levels of monocarboxylate transporters (MCTs), which therefore may constitute suitable therapeutic targets. The impact of MCT inhibition, along with the clinical impact of altered cellular metabolism during prostate cancer (PCa) initiation and progression, has not been described. Using a large cohort of human prostate tissues of different grades, in silico data, in vitro and ex vivo studies, we demonstrate the metabolic heterogeneity of PCa and its clinical relevance. We show an increased glycolytic phenotype in advanced stages of PCa and its correlation with poor prognosis. Finally, we present evidence supporting MCTs as suitable targets in PCa, affecting not only cancer cell proliferation and survival but also the expression of a number of hypoxia‐inducible factor target genes associated with poor prognosis. Herein, we suggest that patients with highly glycolytic tumours have poorer outcome, supporting the notion of targeting glycolytic tumour cells in prostate cancer through the use of MCT inhibitors. © 2015 Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.  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