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81.
We propose a multiple imputation method to deal with incomplete categorical data. This method imputes the missing entries using the principal component method dedicated to categorical data: multiple correspondence analysis (MCA). The uncertainty concerning the parameters of the imputation model is reflected using a non-parametric bootstrap. Multiple imputation using MCA (MIMCA) requires estimating a small number of parameters due to the dimensionality reduction property of MCA. It allows the user to impute a large range of data sets. In particular, a high number of categories per variable, a high number of variables or a small number of individuals are not an issue for MIMCA. Through a simulation study based on real data sets, the method is assessed and compared to the reference methods (multiple imputation using the loglinear model, multiple imputation by logistic regressions) as well to the latest works on the topic (multiple imputation by random forests or by the Dirichlet process mixture of products of multinomial distributions model). The proposed method provides a good point estimate of the parameters of the analysis model considered, such as the coefficients of a main effects logistic regression model, and a reliable estimate of the variability of the estimators. In addition, MIMCA has the great advantage that it is substantially less time consuming on data sets of high dimensions than the other multiple imputation methods.  相似文献   
82.
Generally, the semiclosed-form option pricing formula for complex financial models depends on unobservable factors such as stochastic volatility and jump intensity. A popular practice is to use an estimate of these latent factors to compute the option price. However, in many situations this plug-and-play approximation does not yield the appropriate price. This article examines this bias and quantifies its impacts. We decompose the bias into terms that are related to the bias on the unobservable factors and to the precision of their point estimators. The approximated price is found to be highly biased when only the history of the stock price is used to recover the latent states. This bias is corrected when option prices are added to the sample used to recover the states' best estimate. We also show numerically that such a bias is propagated on calibrated parameters, leading to erroneous values. The Canadian Journal of Statistics 48: 8–35; 2020 © 2019 Statistical Society of Canada  相似文献   
83.
A common approach taken in high‐dimensional regression analysis is sliced inverse regression, which separates the range of the response variable into non‐overlapping regions, called ‘slices’. Asymptotic results are usually shown assuming that the slices are fixed, while in practice, estimators are computed with random slices containing the same number of observations. Based on empirical process theory, we present a unified theoretical framework to study these techniques, and revisit popular inverse regression estimators. Furthermore, we introduce a bootstrap methodology that reproduces the laws of Cramér–von Mises test statistics of interest to model dimension, effects of specified covariates and whether or not a sliced inverse regression estimator is appropriate. Finally, we investigate the accuracy of different bootstrap procedures by means of simulations.  相似文献   
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This study used path analysis to examine the relationship between perceived barriers, acculturation, and role model influence on the career self‐efficacy and career considerations of a sample of Hispanic women. Two path models were examined. The male‐dominated model accounted for 15% of the variance, and the female‐dominated model accounted for 26% of the variance. No relationship was found between the variables of interest and male‐dominated career self‐efficacy and consideration. However, perceived barriers were related to female‐dominated career consideration and Anglo acculturation significantly contributed to female‐dominated career self‐efficacy. Results are discussed with regard to career practice and research with Hispanic women.  相似文献   
88.
This paper investigates how individuals evaluate delayed outcomes with risky realization times. Under the discounted expected utility (DEU) model, such evaluations depend only on intertemporal preferences. We obtain several testable hypotheses using the DEU model as a benchmark and test these hypotheses in three experiments. In general, our results show that the DEU model is a poor predictor of intertemporal choice behavior under timing risk. We found that individuals are averse to timing risk and that they evaluate timing lotteries in a rank-dependent fashion. The main driver of timing risk aversion is nothing but probabilistic risk aversion that stems from the nonlinear treatment of probabilities.  相似文献   
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According to the Census Bureau, 21.9 percent of children in the United States in 1992 were poor (25 percent if one considers only those under six). Those 14.6 million children comprise 40 percent of the total population living below the poverty line. This essay documents their plight, examines the secondary effects of poverty upon the person and community, analyzes why the current “subsidy” approach has been ineffective, seeks a holistic explanation for poverty, and proposes a universal approach based on “supplementation” and “empowerment.” Due to the present budget deficit, the program is designed to be revenue neutral; it should not require any additional taxes.  相似文献   
90.
The policy makers usually assume that the nuclear family model is almost universally favoured in our industrial and urban society. Governmental agencies are thus left with the responsibility taken over in the past by the extended family. Gerontological literature studied the family support available to the elderly. In general, research results have supported the modified extended family model. Here, the multigenerational household is defined as a living arrangement in contradiction with the nuclear family model, but able to provide support to the disabled elderly. With three random samples of non-institutionalized francophone elderly, it was possible to estimate the number of elderly people living in multigenerational households. It was observed that the elderly in such households are older and more functionally impaired than the elderly living in other kinds of households. Thus, the multigenerational household offers a potential for support neglected by policy makers. Governmental agencies should see themselves as supporters of family involvement with elderly members rather than as surrogates for the family. Les planificateurs assument que la famille nucléaire est le modèle presqu'unique adopte par les families de sociétés industrielles et urbaines. Les agences gouvernementales doivent done prendre la reléve de la famille ètendue. Les recherches en gérontologie ont pourtant démontrv que l'aide familiale est disponible aux personnes âgées. En fait, la famille contemporaine assure la plus grande part de l'aide aux personnes âgées. Le ménage multi-générationel se pose en source importante de support pour la personne âgée qui en est membre. L'observation de trois échantillons aléatoires de personnes âgées urbaines et francophones permet une estimation du nombre de personnes âgées habitant dans un ménage multigénérationel. En plus, ces personnes sont plus âgées et ont plus d'incapacités fonctionnelles que les personnes âgées seules ou vivant avec leur conjoint seulement. En conséquence, la famille nucléaire n'est pas un modèle empiriquement adéquat. Les recherches ont plutôt proposé le modèle de la famille étendue modifiée. Les agences gouvernementales devraient concevoir leur rôle en fonction du support qu'offre la famille â ses membres âgés plutôt que de se définir comme substituts familiaux.  相似文献   
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