全文获取类型
收费全文 | 971篇 |
免费 | 29篇 |
国内免费 | 7篇 |
专业分类
1007篇 |
出版年
2025年 | 8篇 |
2024年 | 3篇 |
2023年 | 19篇 |
2022年 | 12篇 |
2021年 | 25篇 |
2020年 | 19篇 |
2019年 | 17篇 |
2018年 | 16篇 |
2017年 | 27篇 |
2016年 | 38篇 |
2015年 | 27篇 |
2014年 | 67篇 |
2013年 | 38篇 |
2012年 | 62篇 |
2011年 | 75篇 |
2010年 | 52篇 |
2009年 | 41篇 |
2008年 | 46篇 |
2007年 | 48篇 |
2006年 | 53篇 |
2005年 | 46篇 |
2004年 | 44篇 |
2003年 | 35篇 |
2002年 | 29篇 |
2001年 | 23篇 |
2000年 | 24篇 |
1999年 | 27篇 |
1998年 | 21篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 9篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有1007条查询结果,搜索用时 15 毫秒
481.
针对基于多传感器组网进行机动目标跟踪的传感器管理问题,提出了一种基于Rényi信息增量的机动目标协同跟踪算法。首先结合\"当前\"统计模型和交互式多模型不敏卡尔曼滤波算法设计了一种变结构多模型算法,来进行机动目标的状态估计;然后以Rényi信息增量为评价准则,选择使Rényi信息增量最大的单个传感器进行目标跟踪;最后利用得到的最优加速度估计进行网格划分,更新变结构多模型中的模型集合。在一般机动及强机动场景下进行了算法性能分析,仿真结果表明,该算法能够合理地选择传感器,提高了对机动目标的跟踪精度。 相似文献
482.
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
483.
ERIC GATES 《Defence and Peace Economics》2013,24(6):509-517
This paper offers the personal view of a senior executive in the Defence Procurement Agency about the future requirements of the defence industry’s principal UK customer. The focus here is on trying to identify the type of corporate behaviour and range of skill sets that the UK Government will need from defence suppliers, both primes and supply chain companies in the future. The concluding message from this ‘Customer View’ is that there is likely to be a continuing market for the company that specializes in delivering defence capability. It will be a company that will be looking for a long‐term relationship, with a specialist knowledge of its various national customers and a willingness to work openly and closely with them. It will be agile in its ability to bring together diverse technologies, to package them as a system and to deliver them either as hardware or as a service. Such suppliers will also need to innovate and to adapt at least as rapidly as the threats that they seek to counter. 相似文献
484.
Assemble‐to‐order (ATO) is an important operational strategy for manufacturing firms to achieve quick response to customer orders while keeping low finished good inventories. This strategy has been successfully used not only by manufacturers (e.g., Dell, IBM) but also by retailers (e.g., Amazon.com). The evaluation of order‐based performance is known to be an important but difficult task, and the existing literature has been mainly focused on stochastic comparison to obtain performance bounds. In this article, we develop an extremely simple Stein–Chen approximation as well as its error‐bound for order‐based fill rate for a multiproduct multicomponent ATO system with random leadtimes to replenish components. This approximation gives an expression for order‐based fill rate in terms of component‐based fill rates. The approximation has the property that the higher the component replenishment leadtime variability, the smaller the error bound. The result allows an operations manager to analyze the improvement in order‐based fill rates when the base‐stock level for any component changes. Numerical studies demonstrate that the approximation performs well, especially when the demand processes of different components are highly correlated; when the components have high base‐stock levels; or when the component replenishment leadtimes have high variability. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012 相似文献
485.
\"新三论\"(包括耗散结构论、协同学和突变论)作为一种新的世界观,给研究作战系统这个复杂的非线性系统提供了新的视角。运用\"新三论\"的思想和方法指出作战系统的序参量,建立序参量方程,分析序参量演化稳定性与途径,得出一些有价值的结论,对于探索作战系统发展演变的规律具有重要意义。 相似文献
486.
平行度测量是舰船设备系统标校的前提,传统的平行度测量方法需要依赖\"星\"或\"标\"的配合,由于舰船所在位置的限制,可能不具备设置\"星\"或\"标\"的条件,利用夜空的星星也很受限。为克服环境条件对标校的限制,可以采用角速率陀螺作为传感器动态测量指向设备的平行度,推出了计算俯仰和旋回零位误差的公式,并对器件误差的影响进行了估算,计算结果说明现有的角速率陀螺器件的精度能满足本测量方法的需求。该研究成果可在舰船设备系统标校中运用,以克服传统方法依赖外界条件的难题。 相似文献
487.
488.
489.
应用离散事件动态系统仿真的基本理论,建立了地空导弹兵混编群作战过程仿真模型,并用Arena仿真平台实现了仿真。通过仿真实例,分析了不同空袭目标流密度和空袭目标采取低空突防时对目标突防概率的影响。仿真结果表明,在该实例中,增大空袭目标流密度对目标突防概率没有显著的影响,而采取低空突防对目标突防概率影响显著。最后,对仿真结果进行了分析,证明了仿真模型的有效性。 相似文献
490.
In this article, we seek to understand how a capacity‐constrained seller optimally prices and schedules product shipping to customers who are heterogeneous on willingness to pay (WTP) and willingness to wait (WTW). The capacity‐constrained seller does not observe each customer's WTP and WTW and knows only the aggregate distributions of WTP and WTW. The seller's problem is modeled as an M/M/Ns queueing model with multiclass customers and multidimensional information screening. We contribute to the literature by providing an optimal and efficient algorithm. Furthermore, we numerically find that customers with a larger waiting cost enjoys a higher scheduling priority, but customers with higher valuation do not necessarily get a higher scheduling priority. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 215–227, 2015 相似文献