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41.
42.
The purpose of this paper is to explain why low-wage workers with identical qualifications to higher-wage workers are more exposed to unemployment. Each worker is considered to belong to a social group (defined according to his/her gender, age, and nationality). We assume that workers experience both productive interdependencies and social interactions within the firm. Also inter- and intra-group interactions determine worker productivity, and frictions on the labor market limit the hiring of the most productive workers. Consequently, externalities acting both within the firm and in the labor market can lead to a higher rate of unemployment for low-wage workers. 相似文献
43.
Capacity planning is one of the most important elements for an efficient production planning and control system. It is even more important when the main strategies to fulfil sales requirements are make-to-order (MTO) or assemble-to-order (ATO). Neither MTO or ATO companies keep finished products in stock which means that production level is driven by actual sales figures. Therefore, it is very important to have an available capacity as flexible as possible to meet sales requirements. Annualized hours (AH) is a work time control system that helps in increasing the flexibility of available capacity. The main rule of the AH system is to hire employees to work a certain number of hours on a yearly basis. Following some other pre-defined rules and limits, the AH system allows a company to adjust weekly available time in order to reduce idle capacity or to fulfil requirements that could mean overtime. This paper proposes a linear programming model to plan the operations using AH. This model has been implemented in a company that produces agricultural implements, showing that it is very simple to use. It is producing excellent practical results. 相似文献
44.
Approximate Bayesian inference on the basis of summary statistics is well-suited to complex problems for which the likelihood
is either mathematically or computationally intractable. However the methods that use rejection suffer from the curse of dimensionality
when the number of summary statistics is increased. Here we propose a machine-learning approach to the estimation of the posterior
density by introducing two innovations. The new method fits a nonlinear conditional heteroscedastic regression of the parameter
on the summary statistics, and then adaptively improves estimation using importance sampling. The new algorithm is compared
to the state-of-the-art approximate Bayesian methods, and achieves considerable reduction of the computational burden in two
examples of inference in statistical genetics and in a queueing model. 相似文献
45.
Fully nonparametric tests for the independence between random vectors are studied in this paper. The test statistics are functionals of an empirical process defined as the difference between the joint empirical copula and the product of the empirical copulas associated to the vectors that are suspected to be independent. The validity of a weighted bootstrap procedure is established, which allows for a quick computation of p-values. A special attention is given to the asymptotic behavior of the tests under contiguous sequences of distributions. Finally, a characteristic of the copulas in the Archimedean class in terms of independence of vectors is exploited in order to propose a new goodness-of-fit procedure. 相似文献
46.
A path scheme for a game is composed of a path, i.e., a sequence of coalitions that is formed during the coalition formation process and a scheme, i.e., a payoff vector for each coalition in the path. A path scheme is called population monotonic if a player’s payoff does not decrease as the path coalition grows. In this study, we focus on Shapley path schemes of simple
games in which for every path coalition the Shapley value of the associated subgame provides the allocation at hand. Obviously,
each Shapley path scheme of a game is population monotonic if and only if the Shapley allocation scheme of the game is population
monotonic in the sense of Sprumont (Games Econ Behav 2:378–394, 1990). We prove that a simple game allows for population monotonic
Shapley path schemes if and only if the game is balanced. Moreover, the Shapley path scheme of a specific path is population
monotonic if and only if the first winning coalition that is formed along the path contains every minimal winning coalition.
We also show that each Shapley path scheme of a simple game is population monotonic if and only if the set of veto players
of the game is a winning coalition. Extensions of these results to other efficient probabilistic values are discussed. 相似文献
47.
48.
Ratelle CF Vallerand RJ Mageau GA Rousseau FL Provencher P 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2004,20(2):105-119
Vallerand et al. (2003) have proposed that individuals can have two distinct types of passion toward an activity. Harmonious passion, an internal force leading one to choose to engage in the activity, is proposed to be associated with positive consequences. Obsessive passion, an internal pressure forcing one to engage in an activity, is posited to be associated with negative consequences. The present study sought to determine the role of the two types of passion in various cognitive and affective states associated with dependence and problems with gambling. Participants (n = 412) were recruited at the Montréal Casino and given a questionnaire measuring passion toward gambling, as well as consequences associated with dependence and problem gambling. Results showed that obsessive passion for gambling predicted poorer vitality and concentration in daily tasks, as well as increased rumination, anxiety, negative mood, guilt, and problem gambling. These relations were not found for harmonious passion for gambling. Results are discussed in light of the motivational approach to passion (Vallerand et al., 2003). 相似文献
49.
In this article, we propose a multivariate random forest method for multiple responses of mixed types with missing responses. Imputation is performed for each bootstrap sample used to build the individual trees that form the forest. The individual trees are built using a weighted splitting rule allowing downweighting of imputed observations. A simulation study shows the benefits of this approach over complete case analysis when missing responses are missing completely at random and missing at random (MAR). In particular, the gain in prediction accuracy of the proposed method is larger in the MAR case and also increases as the proportion of missing increases. 相似文献
50.
Adolescents like to watch TV and listen to the radio, even on school days, but their day contains, like for all other people, only 24 hours. What do those who use electronic media frequently neglect? Data from 14- and 16-year-old adolescents from 12 European countries and from the USA (EURONET sample) were analyzed (N = 3,250). The correlations between time spent using electronic media (EM) and 15 other daily activities were all negative, which is not surprising given the fact that the sum of all activities is bound to be 24 hours. We, therefore, calculated correlations between electronic media use and the proportions of each other activity within the remaining time. A clear pattern emerged. The method allowed us to identify “mandatory” activities that always have high priority, such as sleeping and attending school, and “optional” activities that enter into competition with electronic media use, including engaging in sports, playing music, leisure reading, and being with friends without media use. As to the mandatory activities, the correlations between media-using time and the proportions of remaining time were positive; relative to the optional activities, the correlations between media-using time and the proportions of remaining time were negative. While one might expect school homework to be regarded as mandatory, the correlation patterns identified it as optional. As to the average electronic media-using times, there were marked differences not only between the individual participants, but also between the countries. While Bulgarian adolescents spent an average of 2.37 hours of a regular school day using electronic media, French adolescents averaged only 1.72 hours. 相似文献