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A framework involving independent competing risks permits observing failures due to a specific cause and failures due to a competing cause, which constitute survival times from the cause of primary interest. Is observing more failures more informative than observing survivals? Intuitively, due to the definitiveness of failures, the answer seems to be the former. However, it has been shown before that this intuition holds when estimating the mean but not the failure rate of the exponential model with a gamma prior distribution for the failure rate. In this article, we address this question at a more general level. We show that for a certain class of distributions failures can be more informative than survivals for prediction of life length and vice versa for some others. We also show that for a large class of lifetime models, failure is less informative than survival for estimating the proportional hazards parameter with gamma, Jeffreys, and uniform priors. We further show that, for this class of lifetime models, on average, failure is more informative than survival for parameter estimation and for prediction. These results imply that the inferential purpose and properties of the lifetime distribution are germane for conducting life tests. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013 相似文献
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利用中间件技术,在不影响现有消防地理信息系统应用的前提下,充分共享警用地理信息系统(PGIS)已有建设成果,实现在消防地理信息系统(FGIS)中调用PGIS大比例尺矢量图等信息数据资源,降低了FGIS建设成本,减轻了业务数据采集、维护压力.并对基于中间件技术的数据对接设计思路、整体架构进行了详细阐述. 相似文献
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在大型复杂产品研制过程中,通过原理样机的各类试验所获得的早期可靠性数据对产品早期可靠性的评估及可靠性设计具有重要意义。文中利用顺序约束模型研究了早期可靠性数据的处理方法,并将早期可靠性数据评估结果应用于可靠性增长计划的制定,从而有效减短了可靠性增长试验的时间。最后,给出了一个实际例子,以说明上述方法的应用。 相似文献
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赵国烨 《中国人民武装警察部队学院学报》2007,23(3):35-37
以专业视野总结了以色列警卫工作的特点,从以色列警卫力量的职责地位、警卫措施、情报信息、选拔训练、后勤保障等方面进行了多角度的剖析,为进一步研究我国警卫理论提供借鉴。 相似文献
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E‐commerce platforms afford retailers unprecedented visibility into customer purchase behavior and provide an environment in which prices can be updated quickly and cheaply in response to changing market conditions. This study investigates dynamic pricing strategies for maximizing revenue in an Internet retail channel by actively learning customers' demand response to price. A general methodology is proposed for dynamically pricing information goods, as well as other nonperishable products for which inventory levels are not an essential consideration in pricing. A Bayesian model of demand uncertainty involving the Dirichlet distribution or a mixture of such distributions as a prior captures a wide range of beliefs about customer demand. We provide both analytic formulas and efficient approximation methods for updating these prior distributions after sales data have been observed. We then investigate several strategies for sequential pricing based on index functions that consider both the potential revenue and the information value of selecting prices. These strategies require a manageable amount of computation, are robust to many types of prior misspecification, and yield high revenues compared to static pricing and passive learning approaches. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献