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   325篇
  免费   15篇
管理学   39篇
民族学   2篇
人口学   30篇
丛书文集   1篇
理论方法论   27篇
综合类   3篇
社会学   129篇
统计学   109篇
  2023年   4篇
  2021年   2篇
  2020年   15篇
  2019年   23篇
  2018年   28篇
  2017年   28篇
  2016年   35篇
  2015年   6篇
  2014年   15篇
  2013年   52篇
  2012年   35篇
  2011年   20篇
  2010年   10篇
  2009年   13篇
  2008年   6篇
  2007年   6篇
  2006年   3篇
  2005年   4篇
  2004年   5篇
  2003年   6篇
  2002年   3篇
  2001年   6篇
  2000年   4篇
  1999年   1篇
  1997年   4篇
  1996年   1篇
  1995年   2篇
  1987年   1篇
  1979年   1篇
  1973年   1篇
排序方式: 共有340条查询结果,搜索用时 328 毫秒
301.
Emerging diseases (ED) can have devastating effects on agriculture. Consequently, agricultural insurance for ED can develop if basic insurability criteria are met, including the capability to estimate the severity of ED outbreaks with associated uncertainty. The U.S. farm‐raised channel catfish (Ictalurus punctatus) industry was used to evaluate the feasibility of using a disease spread simulation modeling framework to estimate the potential losses from new ED for agricultural insurance purposes. Two stochastic models were used to simulate the spread of ED between and within channel catfish ponds in Mississippi (MS) under high, medium, and low disease impact scenarios. The mean (95% prediction interval (PI)) proportion of ponds infected within disease‐impacted farms was 7.6% (3.8%, 22.8%), 24.5% (3.8%, 72.0%), and 45.6% (4.0%, 92.3%), and the mean (95% PI) proportion of fish mortalities in ponds affected by the disease was 9.8% (1.4%, 26.7%), 49.2% (4.7%, 60.7%), and 88.3% (85.9%, 90.5%) for the low, medium, and high impact scenarios, respectively. The farm‐level mortality losses from an ED were up to 40.3% of the total farm inventory and can be used for insurance premium rate development. Disease spread modeling provides a systematic way to organize the current knowledge on the ED perils and, ultimately, use this information to help develop actuarially sound agricultural insurance policies and premiums. However, the estimates obtained will include a large amount of uncertainty driven by the stochastic nature of disease outbreaks, by the uncertainty in the frequency of future ED occurrences, and by the often sparse data available from past outbreaks.  相似文献   
302.
This paper demonstrates a connection between data envelopment analysis (DEA) and a non-interactive elicitation method to estimate the weights of objectives for decision-makers in a multiple attribute approach. This connection gives rise to a modified DEA model that allows us to estimate not only efficiency measures but also preference weights by radially projecting each unit onto a linear combination of the elements of the payoff matrix (which is obtained by standard multicriteria methods). For users of multiple attribute decision analysis the basic contribution of this paper is a new interpretation in terms of efficiency of the non-interactive methodology employed to estimate weights in a multicriteria approach. We also propose a modified procedure to calculate an efficient payoff matrix and a procedure to estimate weights through a radial projection rather than a distance minimization. For DEA users, we provide a modified DEA procedure to calculate preference weights and efficiency measures that does not depend on any observations in the dataset. This methodology has been applied to an agricultural case study in Spain.  相似文献   
303.
The objective of the present study was to integrate the relative risk from mercury exposure to stream biota, groundwater, and humans in the Río Artiguas (Sucio) river basin, Nicaragua, where local gold mining occurs. A hazard quotient was used as a common exchange rate in probabilistic estimations of exposure and effects by means of Monte Carlo simulations. The endpoint for stream organisms was the lethal no‐observed‐effect concentration (NOECs), for groundwater the WHO guideline and the inhibitory Hg concentrations in bacteria (IC), and for humans the tolerable daily intake (TDI) and the benchmark dose level with an uncertainty factor of 10 (BMDLs0.1). Macroinvertebrates and fish in the contaminated river are faced with a higher risk to suffer from exposure to Hg than humans eating contaminated fish and bacteria living in the groundwater. The river sediment is the most hazardous source for the macroinvertebrates, and macroinvertebrates make up the highest risk for fish. The distribution of body concentrations of Hg in fish in the mining areas of the basin may exceed the distribution of endpoint values with close to 100% probability. Similarly, the Hg concentration in cord blood of humans feeding on fish from the river was predicted to exceed the BMDLs0.1 with about 10% probability. Most of the risk to the groundwater quality is confined to the vicinity of the gold refining plants and along the river, with a probability of about 20% to exceed the guideline value.  相似文献   
304.
Estimating the sizes of hard-to-count populations is a challenging and important problem that occurs frequently in social science, public health, and public policy. This problem is particularly pressing in HIV/AIDS research because estimates of the sizes of the most at-risk populations-illicit drug users, men who have sex with men, and sex workers-are needed for designing, evaluating, and funding programs to curb the spread of the disease. A promising new approach in this area is the network scale-up method, which uses information about the personal networks of respondents to make population size estimates. However, if the target population has low social visibility, as is likely to be the case in HIV/AIDS research, scale-up estimates will be too low. In this paper we develop a game-like activity that we call the game of contacts in order to estimate the social visibility of groups, and report results from a study of heavy drug users in Curitiba, Brazil (n = 294). The game produced estimates of social visibility that were consistent with qualitative expectations but of surprising magnitude. Further, a number of checks suggest that the data are high-quality. While motivated by the specific problem of population size estimation, our method could be used by researchers more broadly and adds to long-standing efforts to combine the richness of social network analysis with the power and scale of sample surveys.  相似文献   
305.
Underage drinking continues to be a public health concern, partially due to the ease in which adolescents obtain alcohol and consume it in private locations. States and municipalities have implemented strategies to counteract this, including adopting public policies called social host policies, despite limited evidence of effectiveness. Traditionally, these laws have held adults accountable for furnishing alcohol to underage drinkers. However, states and communities are using another policy, also called social host, to deter underage drinking parties where easy access to alcohol and high-risk use occurs. These innovative laws hold individuals who control the property accountable for underage drinking that occurs there, regardless of alcohol source. We conducted a critical analysis of social host policies focused on hosting underage drinking parties and constructed a conceptual model to understand their targeted factors. Future research recommendations are discussed.  相似文献   
306.
Electrical systems can be categorized as critical systems where failure can result in significant financial loss, injury or threats to human life. The operators of the electric power control centers perform an activity in a specialized environment and have to carry it out by mobilizing knowledge and reasoning to which they have adequate training under the terms of the existing rules. To reach this there is a common mental request of personnel involved in these centers due the need to maintain attention, memory and reasoning request. In this sense, this study aims to evaluate the Mental Workload of technical workers of the Control Centers of Electrical Energy. It was undertaken a research on operators control centers of the electricity sector in Northeast Brazil. It was used for systematic observations, followed by interview and application of the instrument National Aeronautics and Space Administration Task Load Index known as NASA-TLX. As a result there will be subsidies for an assessment of mental workload of operators, and a contribution to improving the processes of managing the operation of electric utilities and the quality of workers.  相似文献   
307.
Alterations made in the architectural design can be considered as a continuous process, from its conception to the moment a built environment is already in use. This article focuses on the "moving phase", which is the initial moment of the environment occupation and the start-up of services. It aims to show that the continuity of ergonomics interventions during the "moving phase" or start up may reveal the built environment inadequacies; clearly showing needs not met by the design and allowing making instant decisions to solve non-foreseen problems. The results have revealed some lessons experienced by users during a critical stage not usually included in the design process.  相似文献   
308.
The aim of this paper is to measure the effectiveness of the organizations Information and Communication Technology (ICT) from the point of view of the manager, using Item Response Theory (IRT). There is a need to verify the effectiveness of these organizations which are normally associated to complex, dynamic, and competitive environments. In academic literature, there is disagreement surrounding the concept of organizational effectiveness and its measurement. A construct was elaborated based on dimensions of effectiveness towards the construction of the items of the questionnaire which submitted to specialists for evaluation. It demonstrated itself to be viable in measuring organizational effectiveness of ICT companies under the point of view of a manager through using Two-Parameter Logistic Model (2PLM) of the IRT. This modeling permits us to evaluate the quality and property of each item placed within a single scale: items and respondents, which is not possible when using other similar tools.  相似文献   
309.
Industrial work is a very active sector in the economy of countries; an important part of people's work is done using the upper extremities. The purpose of this project is to characterize the effect of upper extremity work, analyze its relationship with the hand strength and the presence of fatigue and develop a model with the ability to estimate recovery times for the shoulder using variables different from the biomechanical variables.  相似文献   
310.
Warnings are intended to reduce accidents caused by hazards. Behavioral compliance is the most important measure of warning effectiveness. However, in result of diverse circumstances (e.g., distraction, misuse, negligence), conflicting or ambiguous safety messages can be perceived. Since these are recurrent and can result in wrong behaviors encompassing severe consequences, such cases should be studied for safety purposes. We report findings on the participants' compliant behavior when performing a work-related task, while immersed in a virtual environment, and investigate the effect of conflicting messages on compliance with warnings. Two warnings (one regular and one with an appended out-of-order sign) and two types of signs (static and dynamic) were considered. The warning with the out-of-order sign configures the case of potentially conflicting messages. The gender effect was also investigated. The participants' behavior was assessed regarding to pushing a button as directed by the warnings. In the "out-of-order" warning, compliance was higher in the dynamic situation (53.3%) than in the static one (3.3%). Comparing with the non-conflicting warning, compliance was higher for both situations (static: 76.7%; dynamic: 100%). Women complied more than men. Although these results have limitations in their generalization, they are nonetheless relevant and deserve to be studied further.  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