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191.
微电网是智能电网的重要组成部分,可以有效协调区域内的电力资源。为研究面向储能的光伏微网电力成本变化情况和优化对策,基于微网多主体结构构建微网电力成本均衡模型,以微网内分布式光伏供应及用户电力需求的统计数据为主要输入对象,并设置变量来区分不同情景下的分布式可再生能源发电量,建立以时间为自变量的微网分布式电力收益函数和用户购电成本函数,刻画微网电力资源调度的动态均衡变化。基于微网电力资源调度实例,发现微网在并网情景下的购电成本小于储能情景下的购电成本(C并=2 033.6元C储=2 633.6元),且储能情景下购电成本的22.8%都来自储能设施的日折旧费,因此,加大科技研发和增强微网协同管理可以降低微网成本。 相似文献
192.
张静 《淮海工学院学报(社会科学版)》2012,10(9):54-56
为了迎合财务会计的需求,软件公司开发了不少带有逆向操作功能的软件,虽然在使用中对更正会计差错、减少系统数据冗余和提高工作质量等起到了一定的作用,但同样也给财务会计系统的安全带来了威胁。这里在简略介绍会计核算软件逆向操作内涵和功能作用的基础上,针对其可能产生的隐患和危害等进行了分析,并针对其弊端和可能的风险提出了防范性完善措施。 相似文献
193.
《Journal of Statistical Computation and Simulation》2012,82(11):2135-2147
Credit scoring can be defined as the set of statistical models and techniques that help financial institutions in their credit decision makings. In this paper, we consider a coarse classification method based on fused least absolute shrinkage and selection operator (LASSO) penalization. By adopting fused LASSO, one can deal continuous as well as discrete variables in a unified framework. For computational efficiency, we develop a penalization path algorithm. Through numerical examples, we compare the performances of fused LASSO and LASSO with dummy variable coding. 相似文献
194.
In risk assessment, the moment‐independent sensitivity analysis (SA) technique for reducing the model uncertainty has attracted a great deal of attention from analysts and practitioners. It aims at measuring the relative importance of an individual input, or a set of inputs, in determining the uncertainty of model output by looking at the entire distribution range of model output. In this article, along the lines of Plischke et al., we point out that the original moment‐independent SA index (also called delta index) can also be interpreted as the dependence measure between model output and input variables, and introduce another moment‐independent SA index (called extended delta index) based on copula. Then, nonparametric methods for estimating the delta and extended delta indices are proposed. Both methods need only a set of samples to compute all the indices; thus, they conquer the problem of the “curse of dimensionality.” At last, an analytical test example, a risk assessment model, and the levelE model are employed for comparing the delta and the extended delta indices and testing the two calculation methods. Results show that the delta and the extended delta indices produce the same importance ranking in these three test examples. It is also shown that these two proposed calculation methods dramatically reduce the computational burden. 相似文献
195.
In this paper, a new generalization of alpha-skew-normal distribution is considered. Some properties of this distribution, which is denoted by GASN(α, λ), including moments, maximum likelihood estimation of parameters, and some other properties are studied. Finally, using a real data set, we show that our new distribution is the best-fitted distribution for the used data among normal, skew normal, alpha-skew-normal, and skew-bimodal-normal distributions. 相似文献
196.
柏培文 《厦门大学学报(哲学社会科学版)》2012,(4):82-89
估算全国和省际人力资本水平是经济增长研究所不能回避的问题。当前的研究主要采用教育年限法、物质投入法、生产函数法、人力资本回报法、人力资本特征与收入法和J-F终生收入法等六种方法。多角度比较和判别,可以验证生产函数法测算的各年相对人力资本水平较为可靠。使用生产函数法估算全国和各省的1952-2008年的人力资本存量,可刻画统一单位衡量的全国和各省人力资本水平。总体来说,全国和各省人力资本水平呈增长状态,各省人力资本存量以及增长速度存在明显差异。 相似文献
197.
《Journal of Statistical Computation and Simulation》2012,82(4):415-426
This paper considers the problem where the linear discriminant rule is formed from training data that are only partially classified with respect to the two groups of origin. A further complication is that the data of unknown origin do not constitute an observed random sample from a mixture of the two under- lying groups. Under the assumption of a homoscedastic normal model, the overall error rate of the sample linear discriminant rule formed by maximum likelihood from the partially classified training data is derived up to and including terms of the first order in the case of univariate feature data. This first- order expansion of the sample rule so formed is used to define its asymptotic efficiency relative to the rule formed from a completely classified random training set and also to the rule formed from a completely unclassified random set. 相似文献
198.
Ying-Ying Zhang Ze-Yu Wang Zheng-Min Duan Wen Mi 《Journal of Statistical Computation and Simulation》2019,89(16):3061-3074
For the hierarchical Poisson and gamma model, we calculate the Bayes posterior estimator of the parameter of the Poisson distribution under Stein's loss function which penalizes gross overestimation and gross underestimation equally and the corresponding Posterior Expected Stein's Loss (PESL). We also obtain the Bayes posterior estimator of the parameter under the squared error loss and the corresponding PESL. Moreover, we obtain the empirical Bayes estimators of the parameter of the Poisson distribution with a conjugate gamma prior by two methods. In numerical simulations, we have illustrated: The two inequalities of the Bayes posterior estimators and the PESLs; the moment estimators and the Maximum Likelihood Estimators (MLEs) are consistent estimators of the hyperparameters; the goodness-of-fit of the model to the simulated data. The numerical results indicate that the MLEs are better than the moment estimators when estimating the hyperparameters. Finally, we exploit the attendance data on 314 high school juniors from two urban high schools to illustrate our theoretical studies. 相似文献
199.
Conditional and marginal estimates in case-control family data – extensions and sensitivity analyses
《Journal of Statistical Computation and Simulation》2012,82(10):1449-1470
This work considers two specific estimation techniques for the family-specific proportional hazards model and for the population-averaged proportional hazards model. So far, these two estimation procedures were presented and studied under the gamma frailty distribution mainly because of its simple interpretation and mathematical tractability. Modifications of both procedures for other frailty distributions, such as the inverse Gaussian, positive stable and a specific case of discrete distribution, are presented. By extensive simulations, it is shown that under the family-specific proportional hazards model, the gamma frailty model appears to be robust to frailty distribution mis-specification in both bias and efficiency loss in the marginal parameters. The population-averaged proportional hazards model, is found to be robust under the gamma frailty model mis-specification only under moderate or weak dependency within cluster members. 相似文献
200.
The Colorectal Cancer Control Program (CRCCP) provided funding to 29 grantees to increase colorectal cancer screening. We describe the screening promotion costs of CRCCP grantees to evaluate the extent to which the program model resulted in the use of funding to support interventions recommended by the Guide to Community Preventive Services (Community Guide). We analyzed expenditures for screening promotion for the first three years of the CRCCP to assess cost per promotion strategy, and estimated the cost per person screened at the state level based on various projected increases in screening rates. All grantees engaged in small media activities and more than 90% used either client reminders, provider assessment and feedback, or patient navigation. Based on all expenditures, projected cost per eligible person screened for a 1%, 5%, and 10% increase in state-level screening proportions are $172, $34, and $17, respectively. CRCCP grantees expended the majority of their funding on Community Guide recommended screening promotion strategies but about a third was spent on other interventions. Based on this finding, future CRC programs should be provided with targeted education and information on evidence-based strategies, rather than broad based recommendations, to ensure that program funds are expended mainly on evidence-based interventions. 相似文献