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991.
In this paper, we propose a new Bayesian inference approach for classification based on the traditional hinge loss used for classical support vector machines, which we call the Bayesian Additive Machine (BAM). Unlike existing approaches, the new model has a semiparametric discriminant function where some feature effects are nonlinear and others are linear. This separation of features is achieved automatically during model fitting without user pre-specification. Following the literature on sparse regression of high-dimensional models, we can also identify the irrelevant features. By introducing spike-and-slab priors using two sets of indicator variables, these multiple goals are achieved simultaneously and automatically, without any parameter tuning such as cross-validation. An efficient partially collapsed Markov chain Monte Carlo algorithm is developed for posterior exploration based on a data augmentation scheme for the hinge loss. Our simulations and three real data examples demonstrate that the new approach is a strong competitor to some approaches that were proposed recently for dealing with challenging classification examples with high dimensionality.  相似文献   
992.
Hay and Olsen (1984) incorrectly argue that a multi-part model, the two-part model used in Duan et al. (1982,1983), is nested within the sample-selection model. Their proof relies on an unmentioned restrictive assumption that cannot be satisfied. We provide a counterexample to show that the propensity to use medical care and the level of expense can be positively associated in the two-part model, contrary to their assertion. The conditional specification in the multi-part model is preferable to the unconditional specification in the selection model for modeling actual (v. potential) outcomes. The selection model also has poor statistical and numerical properties and relies on untestable assumptions. Empirically the multi-part estimators perform as well as or better than the sample selection estimator for the data set analyzed in Duan et al. (1982, 1983).  相似文献   
993.
Volume 3 of Analysis of Messy Data by Milliken & Johnson (2002) provides detailed recommendations about sequential model development for the analysis of covariance. In his review of this volume, Koehler (2002) asks whether users should be concerned about the effect of this sequential model development on the coverage probabilities of confidence intervals for comparing treatments. We present a general methodology for the examination of these coverage probabilities in the context of the two‐stage model selection procedure that uses two F tests and is proposed in Chapter 2 of Milliken & Johnson (2002). We apply this methodology to an illustrative example from this volume and show that these coverage probabilities are typically very far below nominal. Our conclusion is that users should be very concerned about the coverage probabilities of confidence intervals for comparing treatments constructed after this two‐stage model selection procedure.  相似文献   
994.
This essay takes as its point of critical departure the digital stardom of Susanna Lau, aka Susie Bubble, the most recognizable and respected fashion blogger in the world, in order to consider the historical formation of success in the postmillennial digital economy. By examining Lau as an embodied sign rather than an exceptional figure of success, I am concerned with the technical, cultural, and economic forces that give shape to hegemonic notions of success and the ideal subject it produces. More specifically, I hope to demonstrate the cultural frames that structure our ways of seeing and recognizing successful individuals in the post millennium by highlighting the gendered and racial construction of the ideal Web 2.0 subject. The aim of my discussion is to show that the discursive construction of Lau's success is reflective of emerging global patterns born out of the rising significance of Asians and young women (especially young Asian women) as consumers and producers in the digital economy.  相似文献   
995.
《守望灯塔》是珍妮特·温特森的第八部小说,它开始了一个新的循环。俗话说“他山之石,可以攻玉”。珍妮特·温特森借鉴“他山之石”——德里达的解构主义来“攻玉”——颠覆传统的既定的中心结构——西方逻各斯中心,颠覆权威,解构历史的同时确立自己的女性主义立场,创造自己的神话。  相似文献   
996.
Comparisons of multivariate normal populations are made using a mul-tivariate approach (instead of reducing the problem to a univariate one). A rather negative finding is that, for comparisons with the ‘best’ of each variate, repeated univariate comparisons appear to be almost as efficient as multivariate comparisons, at least for the bivariate case and, under certain circumstances, for higher dimensional cases. Investigations are done on comparisons with the ‘MAX-best’ population (that one having the largest maximum of the marginal means), the ‘MIN-best’ (having the largest minimum) and the ‘O-best’ (being closest to largest in all marginal means). Detailed results are given for the bivariate normal with extensions indicated for the multivariate.  相似文献   
997.
数据挖掘是在大数据中提取客观规律的方法与艺术,如何准确与快速地提取合适的特征变量是其研究的关键问题之一。在模拟分析比较各种数据挖掘算法和提取变量效果的基础上,通过对健康食品市场进行实证研究,指出目前数据挖掘算法存在的不足及发展前景。  相似文献   
998.
19世纪末,达尔文进化论传入中国,其社会影响远大于科学影响,哲学思考远甚于科学研究.但这种解读不是释义上的流误,而是一种对中国近代社会的深刻反思.正是这种反思.使中国哲学告别了封建时代的古典形态,形成了颇具中国气派、中国风格的中国近代进化哲学.它探索和回答了当时正处于内优外患的中国向何处去这一重大社会历史问题,用物竞天择、善变应天的思想观念唤起国人救亡图存的激情和信念,推演出中国近代波澜壮阔的社会运动.同时,它还为马克思主义哲学在中国的传播准备了思想条件.  相似文献   
999.
The predicitive sample reuse (PSR) data analysis technique proposed by Geisser and Eddy (1979) is applied to the analysis of categorical data. This application yiclds a new approach which has a number of advantages over classical methods for analysis of such data. A PSR technique for comparing linear or nonlinar regressino relationships, for two or more populations, and a PSR ailernative to certain nonparaemetri statistical tesis are also proposed.  相似文献   
1000.
Abstract

Forty-seven psychiatric inpatients in a Canadian psychiatric hospital participated in an evaluation of the stability and validity of the Holden Psychological Screening Inventory (HPSI). Stability coefficients over a 1-month period were .85, .79, and .66 for the HPSI Psychiatric, Social, and Depression Symptomatology scales, respectively, and coefficient alpha reliabilities for these scales ranged between .76 and .89 across both time periods. Staff rating composite scales corresponding to the self-report HPSI scales had stability coefficients of .74, .85, and .82, respectively. As well, they had inter-rater reliabilities that ranged between .65 and .84 across both time periods. The 3 staff rating composites at time 1 correlated equivalently with the corresponding 3 primary HPSI scales at times 1 and 2 (p > .05). Similarly, the 3 staff rating composites at time 2 correlated equivalently with the corresponding 3 primary HPSI scales at times 1 and 2 (p > .05). Over a 1-month period, HPSI scale scores were very stable and correlations with criterion ratings were stable. Using a confirmatory factor analysis, with each of the 3 dimensions defined by the time 1 and 2 measures for the 3 HPSI scales and 3 staff rating composites, evidence for discriminant as well as convergent validity was obtained. In summary, the self-report HPSI and the staff rating composite measures evidenced sufficient reliability and validity to meet the requirements for routine clinical assessment work with psychiatric inpatients. Additionally, the stability data provide effects of retesting baseline data for assessing treatment outcome in this population.  相似文献   
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