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991.
《统计学通讯:理论与方法》2013,42(11):2329-2342
In this paper we consider a Markovian perfect debugging model for which the software failure is caused by two types of faults, one which is easily detected and the other which is difficult to detect. When a failure occurs, a perfect debugging is immediately performed and consequently one fault is reduced from fault contents. We also treat the debugging time as a variable to develop a new debugging model. Based on the perfect debugging model, we propose an optimal software release policy that satisfies the requirements for both software reliability and expected number of faults which are required to achieve before releasing the software. Several measures, including the distribution of first passage time to the specified number of removed faults, are also obtained using the proposed debugging model. 相似文献
992.
In this article, we present the effects of three hypothesized protective factors—social activities, school-related activities, and anti–substance use media messages—on adolescent tobacco and alcohol use. Data were drawn from the “Monitoring the Future” research project, which was conducted by the Institute for Social Research at the University of Michigan. The sample included 2,551 twelfth-grade students. The results of the structural equation model showed that exposure to media anti-drug messages had an indirect negative effect on tobacco and alcohol use through school-related activity and social activity. The results suggest that comprehensive ecological interventions encompassing media, family, and school can increase the preventive effects of adolescent's substance use. 相似文献
993.
《Journal Of Human Behavior In The Social Environment》2013,23(3-4):9-29
Abstract This article explores the influence of contextual factors on the developmental outcomes of Mexican American children. The contextual structure of child development is conceptualized as a complex system of environments, including the socio-demographic, social service, academic, and parental home environments. Based on an extensive review of the current theoretical and empirical literature, we find that the disadvantaged social position of Mexican American children has detrimental implications for all other aspects of their environment, thus hindering their development. In addition, although Mexican American parents are highly competent in providing a nurturing and culturally-rich environment, there is a often a discontinuity between the home environment and both the academic and the social service environments. 相似文献
以子博弈完美纳什均衡作为分析工具,分析了电子商务与物流服务发展的不均衡现象,并将网购过程中卖方与快递企业之间的讨价还价过程与贴现因子联系起来,通过模型在节假日期间的应用,从贴现因子对均衡解的影响分析了卖方与快递企业的利益变化。最终得出结论,贴现因子是影响卖方与快递企业所承担的快递费用的重要因素并提出了相应建议。 相似文献
995.
Justus Seely 《The American statistician》2013,67(3):121-123
A proposition is given which provides an easily justified reason as to why attention should be confined to estimable parametric vectors when formulating linear hypotheses. The possibility of justifying one's linear estimation effort on the estimable parametric functions via an identifiability condition is also mentioned. 相似文献
996.
Lawrence S. Evans 《The American statistician》2013,67(2):79-81
Periodically, the pyramid or “chain letter” scheme is offered to Americans under the guise of a business dealership. Recently, the FTC ordered Glen Turner's “Dare to be Great” firm to repay 44 million dollars to participants. In order to demonstrate that the potential gains are misrepresented by promoters, a probability model of the pyramid scheme is developed. The major implications are that the vast majority of participants have less than a ten percent chance of recouping their initial investment when a small profit is achieved as soon as they recruit three people and that, on the average, half of the participants will recruit no one else and lose all their money. 相似文献
997.
Esra Akdeniz Duran 《Journal of Statistical Computation and Simulation》2013,83(5):810-824
The paper introduces a new difference-based Liu estimator β?Ldiff=([Xtilde]′[Xtilde]+I)?1([Xtilde]′[ytilde]+η β?diff) of the regression parameters β in the semiparametric regression model, y=Xβ+f+?. Difference-based estimator, β?diff=([Xtilde]′[Xtilde])?1[Xtilde]′[ytilde] and difference-based Liu estimator are analysed and compared with respect to mean-squared error (mse) criterion. Finally, the performance of the new estimator is evaluated for a real data set. Monte Carlo simulation is given to show the improvement in the scalar mse of the estimator. 相似文献
998.
We propose a semiparametric approach for the analysis of case–control genome-wide association study. Parametric components are used to model both the conditional distribution of the case status given the covariates and the distribution of genotype counts, whereas the distribution of the covariates are modelled nonparametrically. This yields a direct and joint modelling of the case status, covariates and genotype counts, and gives a better understanding of the disease mechanism and results in more reliable conclusions. Side information, such as the disease prevalence, can be conveniently incorporated into the model by an empirical likelihood approach and leads to more efficient estimates and a powerful test in the detection of disease-associated SNPs. Profiling is used to eliminate a nuisance nonparametric component, and the resulting profile empirical likelihood estimates are shown to be consistent and asymptotically normal. For the hypothesis test on disease association, we apply the approximate Bayes factor (ABF) which is computationally simple and most desirable in genome-wide association studies where hundreds of thousands to a million genetic markers are tested. We treat the approximate Bayes factor as a hybrid Bayes factor which replaces the full data by the maximum likelihood estimates of the parameters of interest in the full model and derive it under a general setting. The deviation from Hardy–Weinberg Equilibrium (HWE) is also taken into account and the ABF for HWE using cases is shown to provide evidence of association between a disease and a genetic marker. Simulation studies and an application are further provided to illustrate the utility of the proposed methodology. 相似文献
999.
A class of weighted normal distributions and its variants useful for inequality constrained analysis
Hea-Jung Kim 《Statistics》2013,47(5):421-441
This article develops a class of the weighted normal distributions for which the probability density function has the form of a product of a normal density and a weight function. The class constitutes marginal distributions obtained from various kinds of doubly truncated bivariate normal distributions. This class of distributions strictly includes the normal, skew–normal and two-piece skew–normal and is useful for selection modelling and inequality constrained normal mean analysis. Some distributional properties and Bayesian perspectives of the class are given. Probabilistic representation of the distributions is also given. The representation is shown to be straightforward to specify distribution and to implement computation, with output readily adapted for required analysis. Necessary theories and illustrative examples are provided. 相似文献
1000.
Fisher information contained in record values, inter-record times and their concomitants from a sample of fixed size is derived in general and explicit expressions are deduced for some specific known bivariate classes of distributions. A comparison between fixed sampling and inverse sampling schemes with equal number of records and concomitants is also carried out. We also consider parameter estimation based on bivariate records and a small simulation study is done. 相似文献