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111.
主要研究了网络考试系统设计中利用遗传算法进行智能组卷的问题.首先根据用户对组卷的要求,利用遗传算法对组卷所需的约束条件设置各项指标,利用矩阵理论建立有利于遗传算子进行组合交叉和变异的数学模型;再针对组卷问题中的一个重要约束条件——试卷的难度指标,采用模糊数学方法和项目反应理论对试题库中每一小题进行综合评价试题难度的数学建模,以准确确定每道小题的试题难度系数,最终为实现遗传算法全局寻优和智能搜索奠定基础.  相似文献   
112.
从句法分布、语义指向和语用前提三个方面描述了现代汉语副词"幸亏"的使用特点。在Giannakidou提出的极性词语在(非)真实性语境中得到允准的原则的基础上,对"幸亏"的允准条件进行了探讨。文章论证了"幸亏"具有极端敏感性,需要真实性算子对其进行允准,它的允准条件与肯定极性词一致。  相似文献   
113.
《Journal of homosexuality》2012,59(6):838-854
ABSTRACT

Although academic research on homosexuality relies heavily on survey data, there has been limited study of the survey method of asking relevant questions. This study examines the effect of survey mode on responses to questions about homosexual rights. We find significant mode effects among heterosexual respondents, who are more likely to support equal access to employment, military service, adoption, and marriage for homosexual people in face-to-face surveys than in Web surveys. They are also more likely to choose to not respond when face-to-face than online. Homosexual respondents do not show mode effects for either substantive responses or item nonresponse rate.  相似文献   
114.
The item factor analysis model for investigating multidimensional latent spaces has proved to be useful. Parameter estimation in this model requires computationally demanding high-dimensional integrations. While several approaches to approximate such integrations have been proposed, they suffer various computational difficulties. This paper proposes a Nesting Monte Carlo Expectation-Maximization (MCEM) algorithm for item factor analysis with binary data. Simulation studies and a real data example suggest that the Nesting MCEM approach can significantly improve computational efficiency while also enjoying the good properties of stable convergence and easy implementation.  相似文献   
115.
Summary.  Method effects often occur when different methods are used for measuring the same construct. We present a new approach for modelling this kind of phenomenon, consisting of a definition of method effects and a first model, the method effect model , that can be used for data analysis. This model may be applied to multitrait–multimethod data or to longitudinal data where the same construct is measured with at least two methods at all occasions. In this new approach, the definition of the method effects is based on the theory of individual causal effects by Neyman and Rubin. Method effects are accordingly conceptualized as the individual effects of applying measurement method j instead of k . They are modelled as latent difference scores in structural equation models. A reference method needs to be chosen against which all other methods are compared. The model fit is invariant to the choice of the reference method. The model allows the estimation of the average of the individual method effects, their variance, their correlation with the traits (and other latent variables) and the correlation of different method effects among each other. Furthermore, since the definition of the method effects is in line with the theory of causality, the method effects may (under certain conditions) be interpreted as causal effects of the method. The method effect model is compared with traditional multitrait–multimethod models. An example illustrates the application of the model to longitudinal data analysing the effect of negatively (such as 'feel bad') as compared with positively formulated items (such as 'feel good') measuring mood states.  相似文献   
116.
格雷马斯符号矩阵在国内文学批评实践中存在两种误读情况:一是在部分论著中将符号矩阵第三项和第四项位置颠倒,二是在函项赋值上存在很多偏差,并且缺失整合意识.通过重读符号矩阵,并借鉴杰姆逊运用这一模式分析文本的经典案例,可对上述不足加以修正.  相似文献   
117.
A new characterization for the univariate class of new better than used ‘NBU’ distributions in terms of stochastic ordering is introduced. A multivariate version of this characterization is then used to define a multivariate class of NBU distributions. Basic properties of this class are derived. Comparisons and relationships of this new class with earlier classes are developed. Two multivariate new worse than used (NWU) classes of life distributions are defined and compared and their basic properties are studied.  相似文献   
118.

This article presents, for the first time in English, findings from a Danish research project on language comprehension and memory as generators of measurement problems in sociological and other social-science survey studies. Utilizing survey questionnaires as instruments of measurements, the article deals with the linguistic sensitivity of Danish adults and the measurement problems it entails. The article uncovers the nature and extent of statistically significant response differences due to moderate linguistic changes. The article problematizes the trustworthiness of Danish social-science survey studies and provides evidence that respondents' answers to survey questions depend to a marked extent on the latter's wording. The empirical basis is a split-sample experiment in which 1900 respondents completed two versions of the 'same' questionnaire.  相似文献   
119.
《汉语大词典》"逮(包括其所构成词条)"的释义与书证,皆有可商榷之处单词释义中或义项可以撤消,或义项释义不确;构成的词条或所释不妥;书证或难以说明所释,或句读有误,或裁取不当.  相似文献   
120.
A Novel Evolutionary Formulation of the Maximum Independent Set Problem   总被引:1,自引:1,他引:0  
We introduce a novel evolutionary formulation of the problem of finding a maximum independent set of a graph. The new formulation is based on the relationship that exists between a graphs independence number and its acyclic orientations. It views such orientations as individuals and evolves them with the aid of evolutionary operators that are very heavily based on the structure of the graph and its acyclic orientations. The resulting heuristic has been tested on some of the Second DIMACS Implementation Challenge benchmark graphs, and has been found to be competitive when compared to several of the other heuristics that have also been tested on those graphs.  相似文献   
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