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451.
针对因工艺导致的惯导陀螺存在不平衡质量的问题,讨论了转子在不平衡力偶作用下的运动特性。通过建立转子形体坐标系、惯性主轴坐标系以确定转子主轴相对惯性空间的方位,并分析了转子定向性的变化对惯导飞行控制过程的影响。同时,利用末制导炮弹刚体弹道模型进行了仿真,结果表明:转子铅垂方向以及水平方向的动不平衡角对末制导炮弹的射程和侧偏具有重要的影响。 相似文献
452.
This article is concerned with the determination of pricing strategies for a firm that in each period of a finite horizon receives replenishment quantities of a single product which it sells in two markets, for example, a long‐distance market and an on‐site market. The key difference between the two markets is that the long‐distance market provides for a one period delay in demand fulfillment. In contrast, on‐site orders must be filled immediately as the customer is at the physical on‐site location. We model the demands in consecutive periods as independent random variables and their distributions depend on the item's price in accordance with two general stochastic demand functions: additive or multiplicative. The firm uses a single pool of inventory to fulfill demands from both markets. We investigate properties of the structure of the dynamic pricing strategy that maximizes the total expected discounted profit over the finite time horizon, under fixed or controlled replenishment conditions. Further, we provide conditions under which one market may be the preferred outlet to sale over the other. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 531–549, 2015 相似文献
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In this work, we examine port crane scheduling with spatial and separation constraints. Although common to most port operations, these constraints have not been previously studied. We assume that cranes cannot cross, there is a minimum distance between cranes and jobs cannot be done simultaneously. The objective is to find a crane‐to‐job matching which maximizes throughput under these constraints. We provide dynamic programming algorithms, a probabilistic tabu search, and a squeaky wheel optimization heuristic for solution. Experiments show the heuristics perform well compared with optimal solutions obtained by CPLEX for small scale instances where a squeaky wheel optimization with local search approach gives good results within short times. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004. 相似文献
455.
捷联惯导惯性系对准误差分析 总被引:1,自引:0,他引:1
针对捷联惯导晃动基座下惯性系粗对准两种不同的计算方法,分析了由陀螺常值漂移和加速度计零偏引起的漂移误差(即平台失准角)、刻度误差和歪斜误差,并推导了这些误差项与惯性元件误差之间关系的解析表达式。结果表明:两种惯性系对准算法的平台失准角具有相同的极限精度,并且与传统解析对准法的精度一致;惯性系对准法的歪斜误差很小可以忽略,但需对姿态阵正交化以消除刻度误差的影响。 相似文献
456.
A mathematical formulation and efficient heuristics for the dynamic container relocation problem 下载免费PDF全文
The container relocation problem (CRP) is concerned with emptying a single yard‐bay which contains J containers each following a given pickup order so as to minimize the total number of relocations made during their retrieval process. The CRP can be modeled as a binary integer programming (IP) problem and is known to be NP‐hard. In this work, we focus on an extension of the CRP to the case where containers are both received and retrieved from a single yard‐bay, and call it the dynamic container relocation problem. The arrival (departure) sequences of containers to (from) the yard‐bay is assumed to be known a priori. A binary IP formulation is presented for the problem. Then, we propose three types of heuristic methods: index based heuristics, heuristics using the binary IP formulation, and a beam search heuristic. Computational experiments are performed on an extensive set of randomly generated test instances. Our results show that beam search heuristic is very efficient and performs better than the other heuristic methods.Copyright © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 101–118, 2014 相似文献
457.
针对无线传感网中结点能量受限,提出了一种基于动态流能量高效的路由算法DFEERA(Dynamic Flow-based Energy-Efficient Routing Algorithm)。该算法通过在无线传感网内设置多个基站收集区域内传感器结点的数据流拓扑结构建立数据传输能量消耗模型,将该模型转换为最大流问题求解最优传输路径,作为某时期内结点数据传输路径。随着结点能量的消耗,动态调整该能量消耗模型重新规划路径,作为新的传输路径,从而平衡结点间的能量消耗,提高网络结点的存活率。仿真结果表明,与其他典型的路由算法相比,DFEERA能够更好地平衡结点的能耗,获得更高的能量消耗率和更长的网络生存期。 相似文献
458.
为节省边(滑)坡灾害的应急加固时间,提高边(滑)坡处置的效率和质量,针对边(滑)坡在勘察阶段提出了基于U型钢板桩施工的动态勘察技术,即在静压植桩机压入U型钢板桩的同时,利用与其配套的压入管理系统设备与软件对压桩数据进行监测和分析,从而反馈出地层强度等信息。数值模拟中,为了能利用工程中所得压桩阻力图谱来反推地层信息,归纳总结了不同土体在桩压入时的应力云图和压桩阻力规律。结果表明:压桩阻力规律与地层信息之间存在对应关系,据此可判断地层强度特征等信息,数值模拟也为后续的现场试验研究提供了依据。 相似文献
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简要介绍陀螺马达驱动信号的数字化测量方法及失真度分析的数学原理 ,给出了一个实例 .实践证明 ,该方法电路结构简单、参数测量准确、程序编写方便 ,具有较好的实时性能 . 相似文献