全文获取类型
收费全文 | 4228篇 |
免费 | 945篇 |
国内免费 | 9篇 |
专业分类
管理学 | 1159篇 |
民族学 | 9篇 |
人才学 | 1篇 |
人口学 | 81篇 |
丛书文集 | 30篇 |
理论方法论 | 834篇 |
综合类 | 316篇 |
社会学 | 1657篇 |
统计学 | 1095篇 |
出版年
2024年 | 4篇 |
2023年 | 4篇 |
2022年 | 10篇 |
2021年 | 105篇 |
2020年 | 181篇 |
2019年 | 342篇 |
2018年 | 218篇 |
2017年 | 368篇 |
2016年 | 365篇 |
2015年 | 353篇 |
2014年 | 389篇 |
2013年 | 595篇 |
2012年 | 382篇 |
2011年 | 288篇 |
2010年 | 287篇 |
2009年 | 169篇 |
2008年 | 216篇 |
2007年 | 130篇 |
2006年 | 121篇 |
2005年 | 112篇 |
2004年 | 121篇 |
2003年 | 91篇 |
2002年 | 97篇 |
2001年 | 105篇 |
2000年 | 78篇 |
1999年 | 14篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有5182条查询结果,搜索用时 15 毫秒
711.
Emerging “prevention‐based” approaches to chemical regulation seek to minimize the use of toxic chemicals by mandating or directly incentivizing the adoption of viable safer alternative chemicals or processes. California and Maine are beginning to implement such programs, requiring manufacturers of consumer products containing certain chemicals of concern to identify and evaluate potential safer alternatives. In the European Union, the REACH program imposes similar obligations on manufacturers of certain substances of very high concern. Effective prevention‐based regulation requires regulatory alternatives analysis (RAA), a methodology for comparing and evaluating the regulated chemical or process and its alternatives across a range of relevant criteria. RAA has both public and private dimensions. To a significant degree, alternatives analysis is an aspect of product design; that is, the process by which private industry designs the goods it sells. Accordingly, an RAA method should reflect the attributes of well‐crafted product design tools used by businesses. But RAA adds health and environmental objectives to the mix of concerns taken into account by the product designer. Moreover, as part of a prevention‐based regulatory regime, it implicates important public values such as legitimacy, equity, public engagement, and accountability. Thus, an RAA should reflect both private standards and public values, and be evaluated against them. This article adopts that perspective, identifying an integrated set of design principles for RAA, and illustrating the application of those principles. 相似文献
712.
Tibor Rutar 《Journal for the theory of social behaviour》2019,49(3):298-311
Most sociologists are not content with merely relating macrosocial phenomena to preceding macrosocial causes in their causal explanations of social phenomena. Instead they are seeking to provide (non‐reductive) microfoundations with which they can corroborate and make understandable the connection between macrosocial phenomena. In order to do so a theory (or theories) of human action is required. One such theory, rational choice theory (RCT), has long been viewed with strong suspicion in sociology. I show such suspicion to be partially justified. RCT cannot be a general theory of social behaviour. Nonetheless, there are important insights in various versions of RCT that should not be discarded. In order to improve upon RCT and move toward a more unified or integrative theory of action social‐psychological research has to be taken note of. I demonstrate how dual‐process theories and the research on heuristics can help sociologists move beyond RCT without contradicting some of its more basic insights. 相似文献
713.
Drawing on a thematic analysis of longitudinal qualitative data (ntotal = 118), this article takes a “whole student lifecycle” approach to examine how lower and higher income students at an English northern red brick university variously attempted to manage their individual budgets. It explores how students reconcile their income—in the form of loans, grants, and bursaries—with the cost of living. Four arenas of interest are described: planning, budgeting, and managing “the student loan”; disruptions to financial planning; the role of familial support; and strategies of augmenting the budget. In detailing the micro‐level constraints on the individual budgets of lower and higher income undergraduates, the article highlights the importance of non‐repayable grants and bursaries in helping to sustain meaningful participation in higher tariff, more selective, higher education institutions. It also supports an emerging body of literature that suggests that the continuing amendments to the system of funding higher education in England are unlikely to address inequality of access, participation, and outcome. 相似文献
714.
715.
In this article, we introduce a framework for analyzing the risk of systems failure based on estimating the failure probability. The latter is defined as the probability that a certain risk process, characterizing the operations of a system, reaches a possibly time‐dependent critical risk level within a finite‐time interval. Under general assumptions, we define two dually connected models for the risk process and derive explicit expressions for the failure probability and also the joint probability of the time of the occurrence of failure and the excess of the risk process over the risk level. We illustrate how these probabilistic models and results can be successfully applied in several important areas of risk analysis, among which are systems reliability, inventory management, flood control via dam management, infectious disease spread, and financial insolvency. Numerical illustrations are also presented. 相似文献
716.
Reducing the Risk of Injury from Table Saw Use: The Potential Benefits and Costs of Automatic Protection 下载免费PDF全文
The use of table saws in the United States is associated with approximately 28,000 emergency department (ED) visits and 2,000 cases of finger amputation per year. This article provides a quantitative estimate of the economic benefits of automatic protection systems that could be designed into new table saw products. Benefits are defined as reduced health‐care costs, enhanced production at work, and diminished pain and suffering. The present value of the benefits of automatic protection over the life of the table saw are interpreted as the switch‐point cost value, the maximum investment in automatic protection that can be justified by benefit‐cost comparison. Using two alternative methods for monetizing pain and suffering, the study finds switch‐point cost values of $753 and $561 per saw. These point estimates are sensitive to the values of inputs, especially the average cost of injury. The various switch‐point cost values are substantially higher than rough estimates of the incremental cost of automatic protection systems. Uncertainties and future research needs are discussed. 相似文献
717.
Risk‐Cost‐Benefit Analysis for Transportation Corridors with Interval Uncertainties of Heterogeneous Data 下载免费PDF全文
Access management, which systematically limits opportunities for egress and ingress of vehicles to highway lanes, is critical to protect trillions of dollars of current investment in transportation. This article addresses allocating resources for access management with incomplete and partially relevant data on crash rates, travel speeds, and other factors. While access management can be effective to avoid crashes, reduce travel times, and increase route capacities, the literature suggests a need for performance metrics to guide investments in resource allocation across large corridor networks and several time horizons. In this article, we describe a quantitative decision model to support an access management program via risk‐cost‐benefit analysis under data uncertainties from diverse sources of data and expertise. The approach quantifies potential benefits, including safety improvement and travel time savings, and costs of access management through functional relationships of input parameters including crash rates, corridor access point densities, and traffic volumes. Parameter uncertainties, which vary across locales and experts, are addressed via numerical interval analyses. This approach is demonstrated at several geographic scales across 7,000 kilometers of highways in a geographic region and several subregions. The demonstration prioritizes route segments that would benefit from risk management, including (i) additional data or elicitation, (ii) right‐of‐way purchases, (iii) restriction or closing of access points, (iv) new alignments, (v) developer proffers, and (vi) etc. The approach ought to be of wide interest to analysts, planners, policymakers, and stakeholders who rely on heterogeneous data and expertise for risk management. 相似文献
718.
Application of the Hyper‐Poisson Generalized Linear Model for Analyzing Motor Vehicle Crashes 下载免费PDF全文
S. Hadi Khazraee Antonio Jose Sáez‐Castillo Srinivas Reddy Geedipally Dominique Lord 《Risk analysis》2015,35(5):919-930
The hyper‐Poisson distribution can handle both over‐ and underdispersion, and its generalized linear model formulation allows the dispersion of the distribution to be observation‐specific and dependent on model covariates. This study's objective is to examine the potential applicability of a newly proposed generalized linear model framework for the hyper‐Poisson distribution in analyzing motor vehicle crash count data. The hyper‐Poisson generalized linear model was first fitted to intersection crash data from Toronto, characterized by overdispersion, and then to crash data from railway‐highway crossings in Korea, characterized by underdispersion. The results of this study are promising. When fitted to the Toronto data set, the goodness‐of‐fit measures indicated that the hyper‐Poisson model with a variable dispersion parameter provided a statistical fit as good as the traditional negative binomial model. The hyper‐Poisson model was also successful in handling the underdispersed data from Korea; the model performed as well as the gamma probability model and the Conway‐Maxwell‐Poisson model previously developed for the same data set. The advantages of the hyper‐Poisson model studied in this article are noteworthy. Unlike the negative binomial model, which has difficulties in handling underdispersed data, the hyper‐Poisson model can handle both over‐ and underdispersed crash data. Although not a major issue for the Conway‐Maxwell‐Poisson model, the effect of each variable on the expected mean of crashes is easily interpretable in the case of this new model. 相似文献
719.
Quantitative risk assessments for physical, chemical, biological, occupational, or environmental agents rely on scientific studies to support their conclusions. These studies often include relatively few observations, and, as a result, models used to characterize the risk may include large amounts of uncertainty. The motivation, development, and assessment of new methods for risk assessment is facilitated by the availability of a set of experimental studies that span a range of dose‐response patterns that are observed in practice. We describe construction of such a historical database focusing on quantal data in chemical risk assessment, and we employ this database to develop priors in Bayesian analyses. The database is assembled from a variety of existing toxicological data sources and contains 733 separate quantal dose‐response data sets. As an illustration of the database's use, prior distributions for individual model parameters in Bayesian dose‐response analysis are constructed. Results indicate that including prior information based on curated historical data in quantitative risk assessments may help stabilize eventual point estimates, producing dose‐response functions that are more stable and precisely estimated. These in turn produce potency estimates that share the same benefit. We are confident that quantitative risk analysts will find many other applications and issues to explore using this database. 相似文献
720.
Galateia Terti Isabelle Ruin Jonathan J. Gourley Pierre Kirstetter Zachary Flamig Juliette Blanchet Ami Arthur Sandrine Anquetin 《Risk analysis》2019,39(1):140-161
This article focuses on conceptual and methodological developments allowing the integration of physical and social dynamics leading to model forecasts of circumstance‐specific human losses during a flash flood. To reach this objective, a random forest classifier is applied to assess the likelihood of fatality occurrence for a given circumstance as a function of representative indicators. Here, vehicle‐related circumstance is chosen as the literature indicates that most fatalities from flash flooding fall in this category. A database of flash flood events, with and without human losses from 2001 to 2011 in the United States, is supplemented with other variables describing the storm event, the spatial distribution of the sensitive characteristics of the exposed population, and built environment at the county level. The catastrophic flash floods of May 2015 in the states of Texas and Oklahoma are used as a case study to map the dynamics of the estimated probabilistic human risk on a daily scale. The results indicate the importance of time‐ and space‐dependent human vulnerability and risk assessment for short‐fuse flood events. The need for more systematic human impact data collection is also highlighted to advance impact‐based predictive models for flash flood casualties using machine‐learning approaches in the future. 相似文献