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   821篇
  免费   21篇
  国内免费   34篇
管理学   76篇
民族学   12篇
人口学   29篇
丛书文集   59篇
理论方法论   59篇
综合类   425篇
社会学   111篇
统计学   105篇
  2024年   2篇
  2023年   6篇
  2022年   11篇
  2021年   10篇
  2020年   12篇
  2019年   26篇
  2018年   15篇
  2017年   28篇
  2016年   21篇
  2015年   25篇
  2014年   70篇
  2013年   118篇
  2012年   43篇
  2011年   41篇
  2010年   38篇
  2009年   50篇
  2008年   53篇
  2007年   47篇
  2006年   37篇
  2005年   43篇
  2004年   24篇
  2003年   32篇
  2002年   28篇
  2001年   27篇
  2000年   14篇
  1999年   9篇
  1998年   10篇
  1997年   6篇
  1996年   7篇
  1995年   3篇
  1994年   5篇
  1993年   4篇
  1992年   2篇
  1991年   3篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1982年   1篇
排序方式: 共有876条查询结果,搜索用时 15 毫秒
1.
Informal caregivers of individuals with Alzheimer's disease spend a considerable amount of time providing care. In this paper, we use Grossman's health production and Becker's time allocation models to develop a model of informal care provision to elderly dementia patients. In our model, time inputs produce caregiving services, which provides utility to the caregiver, but reduces leisure. We assume that time is less productive of services on the margin as the disease progresses. In this framework, an increase in patients' disease severity does not necessarily increase informal caregiver time input. The cost of formal care establishes a reservation price for informal caregiving. When the costs of informal caregiving rise above this reservation level, the patient is institutionalized. We test empirically the effect of deterioration in the patients' condition, proxied by both disease severity and dementia problem behavior, on informal caregiving time. We find that dementia-related problem behaviors and functional limitations significantly increase inputs of informal caregiving time. Patients' problem behavior exerts a modifying effect on functional limitations, and patients' comorbidities have no effect on informal caregiving time.  相似文献   
2.
On Block Updating in Markov Random Field Models for Disease Mapping   总被引:3,自引:0,他引:3  
Gaussian Markov random field (GMRF) models are commonly used to model spatial correlation in disease mapping applications. For Bayesian inference by MCMC, so far mainly single-site updating algorithms have been considered. However, convergence and mixing properties of such algorithms can be extremely poor due to strong dependencies of parameters in the posterior distribution. In this paper, we propose various block sampling algorithms in order to improve the MCMC performance. The methodology is rather general, allows for non-standard full conditionals, and can be applied in a modular fashion in a large number of different scenarios. For illustration we consider three different applications: two formulations for spatial modelling of a single disease (with and without additional unstructured parameters respectively), and one formulation for the joint analysis of two diseases. The results indicate that the largest benefits are obtained if parameters and the corresponding hyperparameter are updated jointly in one large block. Implementation of such block algorithms is relatively easy using methods for fast sampling of Gaussian Markov random fields ( Rue, 2001 ). By comparison, Monte Carlo estimates based on single-site updating can be rather misleading, even for very long runs. Our results may have wider relevance for efficient MCMC simulation in hierarchical models with Markov random field components.  相似文献   
3.
用台湾爆发口蹄疫的案例实证演绎了生猪传染性疫病对猪肉贸易的重大影响。研究认为:疫病预防和控制以及国际认可、国家兽医体制的控制能力以及生猪适度规模饲养是猪肉贸易健康发展的关键因素,因此,作为养猪大国的中国,必须吸取国际经验,完善生猪疫病预防和控制,促进猪肉贸易发展。  相似文献   
4.
Foot and mouth disease (FMD) is considered by many as the most important animal disease in the world. FMD is highly contagious and outbreaks incur significant costs as affected countries are severely limited in their ability to trade. A number of trade commodities may be contaminated with FMD virus (FMDV) including animal products, for example, meat. As a member of the European Union, Great Britain (GB) has put in place a number of regulations to prevent the importation of pathogens in imported meat products. However, the illegal importation of meat provides a route by which safety controls may be circumvented and meat from FMD affected areas may be imported. This study assesses the FMD infection risk posed to the livestock population of GB from the illegal importation of meat, and estimates the major contributors to this overall risk, through the development of a quantitative risk assessment model. From model results, the total amount of illegal meat entering GB each year is estimated on average to be 11,875 tonnes. with 90% certainty that this is between 4,398 and 28,626 tonnes per year; of which between 64.5 and 565 kg are contaminated with FMDV. This flow of illegal meat results in an estimate of a frequency of FMD infection in GB livestock of 0.015 cases of infected animals per year, with 90% certainty it is between 0.0017 and 0.053. Imports from the region Near and Middle East account for 47% of this risk, and 68% of the risk is attributed to bone-in and dried de-boned products.  相似文献   
5.
利用演化博弈模型预测舆论的发展趋势,对政府应对网络群体事件采取的治理模式进行了研究.在一般化复制动态模型基础上建立网络群体事件舆论的传播方程,将地方政府部门与弱势群体的策略互动和行为演化融入到传染病传播模型中,用以模拟舆论的扩散和收敛过程.结果表明:在网络群体事件初期,如果弱势群体通过抗争获得政府补偿的概率不断增大,将造成事态的扩大.此时,地方政府应控制信息的交流程度与初始抗争人数,减缓舆论的扩散;在网络群体事件舆论大范围扩散阶段,上级政府介入并采取惩罚措施,及时披露信息,促使网络舆论的收敛平息,实现社会福利最大化.  相似文献   
6.
ABSTRACT

This article contributes to discussions on the gender dimensions of disease outbreaks, and preparedness policies and responses, by providing a multi-level analysis of gender-related gaps, particularly illustrating how the failure to challenge gender assumptions and incorporate gender as a priority at the global level has national and local impacts. The implications of neglecting gender dynamics, as well as the potential of equity-based approaches to disease outbreak responses, is illustrated through a case study of the Social Enterprise Network for Development (SEND) Sierra Leone, a non-government organisation (NGO) based in Kailahun, during the Ebola outbreak.  相似文献   
7.
We developed a stochastic model for quantitative risk assessment for the Schistosoma mansoni (SM) parasite, which causes an endemic disease of public concern. The model provides answers in a useful format for public health decisions, uses data and expert opinion, and can be applied to any landscape where the snail Biomphalaria glabrata is the main intermediate host (South and Central America, the Caribbean, and Africa). It incorporates several realistic and case‐specific features: stage‐structured parasite populations, periodic praziquantel (PZQ) drug treatment for humans, density dependence, extreme events (prolonged rainfall), site‐specific sanitation quality, environmental stochasticity, monthly rainfall variation, uncertainty in parameters, and spatial dynamics. We parameterize the model through a real‐world application in the district of Porto de Galinhas (PG), one of the main touristic destinations in Brazil, where previous studies identified four parasite populations within the metapopulation. The results provide a good approximation of the dynamics of the system and are in agreement with our field observations, i.e., the lack of basic infrastructure (sanitation level and health programs) makes PG a suitable habitat for the persistence and growth of a parasite metapopulation. We quantify the risk of SM metapopulation explosion and quasi‐extinction and the time to metapopulation explosion and quasi‐extinction. We evaluate the sensitivity of the results under varying scenarios of future periodic PZQ treatment (based on the Brazilian Ministry of Health's plan) and sanitation quality. We conclude that the plan might be useful to slow SM metapopulation growth but not to control it. Additional investments in better sanitation are necessary.  相似文献   
8.
This article aims to construct a risk model for the prediction of foot-and-mouth disease (FMD) entrance caused by passengers who illegally carry meat products of cloven-hoofed animals through international airports into a country. The risk that meat contaminated with the FMD virus is formulated as the probabilities of FMD factor events (the prevalence of FMD), the commodity factor event (the transportation, storage, and distribution (TSD) factor event), and the passenger event. Data used for analysis were records of illegal meat product carriers from areas A and B intercepted at an international airport in Taiwan. A risk model was proposed to simulate the probability distributions in disease prevalence, probability of FMD virus existing in the meat products after meat processing, and estimation of survival of virus and time period for TSD. The probability of the passenger event was hypothesized with the odds of intercepted passengers and estimated via logistic regression. The results showed that the odds of passengers being intercepted by beagles were higher than those intercepted by Customs. By conducting Monte Carlo simulations, the probability of FMD virus risk caused by FMD factors from area A was 149 times lower than that from area B. The probability of FMD virus risk caused by the passenger event from area A was four times lower than the corresponding probability from area B. The model provides a contribution to FMD prevention and can be a reference for developing models of other diseases.  相似文献   
9.
现代医学认为流行病是由各种生物性致病原或称为病原体所引起的一组具有强烈传染性的疾病.而从传统医学角度而言,所谓流行病是指具有温热病性质的急性传染病,属温热病中具有强烈传染性、病情危重凶险并具有大流行特征的一类疾病.在古代文献中,一般称之为疲、疾疲、瘥、札、疠等.宋人也大体承袭了这一提法.通常情况下,疫病与流行病无法确切区分,因此,统称流行病为疾疫或瘟疫.宋代江南地区是流行病的多发区.这大概与江南地区水网密布,气候温湿、人口密集、人员流动频繁、经济较为活跃易于细菌病毒繁殖有关.  相似文献   
10.
在中国诗史上,唐代是寺院诗创作的转进与勃兴期,作品数量及题材拓展均取得极大突破。在书写模式上,相继形成藉景畅理、触境明心、纪实绘景三种类型,充分体现佛教与山水互彰的共生性,为山水诗开拓出全新境界。唐人寺院诗重写景造境,常以动静相生法状清寂之景,物态生动,意境幽玄。寺院诗在艺术表现上追求警策,字锻句炼,隽语频出,普遍形成以精切之语状绝胜之景的艺术效果。  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