首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   473篇
  免费   222篇
  国内免费   20篇
  2024年   1篇
  2023年   9篇
  2022年   6篇
  2021年   9篇
  2020年   11篇
  2019年   12篇
  2018年   8篇
  2017年   31篇
  2016年   42篇
  2015年   27篇
  2014年   43篇
  2013年   56篇
  2012年   35篇
  2011年   46篇
  2010年   39篇
  2009年   37篇
  2008年   38篇
  2007年   41篇
  2006年   31篇
  2005年   30篇
  2004年   35篇
  2003年   24篇
  2002年   10篇
  2001年   16篇
  2000年   15篇
  1999年   8篇
  1998年   9篇
  1997年   6篇
  1996年   7篇
  1995年   4篇
  1994年   6篇
  1993年   6篇
  1992年   4篇
  1991年   1篇
  1990年   6篇
  1989年   4篇
  1988年   1篇
  1975年   1篇
排序方式: 共有715条查询结果,搜索用时 46 毫秒
71.
对贫困大学生心理健康教育的思考   总被引:2,自引:0,他引:2  
贫困大学生不仅经济上困难,而且还存在许多心理问题。研究高校贫困大学生的心理状况,并对他们进行心理健康教育,可为高校教育工作的针对性和有效性提供帮助。  相似文献   
72.
This article presents new tools and methods for finding optimum step‐stress accelerated life test plans. First, we present an approach to calculate the large‐sample approximate variance of the maximum likelihood estimator of a quantile of the failure time distribution at use conditions from a step‐stress accelerated life test. The approach allows for multistep stress changes and censoring for general log‐location‐scale distributions based on a cumulative exposure model. As an application of this approach, the optimum variance is studied as a function of shape parameter for both Weibull and lognormal distributions. Graphical comparisons among test plans using step‐up, step‐down, and constant‐stress patterns are also presented. The results show that depending on the values of the model parameters and quantile of interest, each of the three test plans can be preferable in terms of optimum variance. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008  相似文献   
73.
A method is presented to locate and allocate p new facilities in relation to n existing facilities. Each of the n existing facilities has a requirement flow which must be supplied by the new facilities. Rectangular distances are assumed to exist between all facilities. The algorithm proceeds in two stages. In the first stage a set of all possible optimal new facility locations is determined by a set reduction algorithm. The resultant problem is shown to be equivalent to finding the p-median of a weighted connected graph. In the second stage the optimal locations and allocations are obtained by using a technique for solving the p-median problem.  相似文献   
74.
基于案例推理和模糊诊断的兵器故障诊断专家系统   总被引:5,自引:0,他引:5  
讨论了基于案例的推理和模糊诊断矩阵在兵器故障中的应用 ,建立了兵器故障诊断WDDS -E系统模型和模糊诊断矩阵模型。详细说明了系统的工作原理和设计过程 ,并给出了应用实例  相似文献   
75.
模糊综合评判的混合决策算法   总被引:2,自引:0,他引:2  
通过对多指标评判的分析 ,结合模糊评价方法的特点 ,论述了一种多指标模糊综合评判的混合决策算法。在模糊综合评判的取大取小算法的基础上 ,给出一种比较好的模糊综合评价的混合算法  相似文献   
76.
In this paper a constraint proposal method is developed for computing Pareto‐optimal solutions in multiparty negotiations over continuous issues. Constraint proposal methods have been previously studied in a case where the decision set is unconstrained. Here we extend the method to situations with a constrained decision set. In the method the computation of the Pareto‐optimal solutions is decentralized so that the DMs do not have to know each others' value functions. During the procedure they have to indicate their optimal solutions on different sets of linear constraints. When the optimal solutions coincide, the common optimum is a candidate for a Pareto‐optimal point. The constraint proposal method can be used to generate either one Pareto‐optimal solution dominating the status quo solution or several Pareto‐optimal solutions. In latter case a distributive negotiation among the efficient points can be carried out afterwards. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 210–225, 2001  相似文献   
77.
采用分层介质膜的等效模型 ,计算了均匀光纤光栅及线性啁啾光栅的反射谱、透射谱及反射相位跃变 ,结果与采用耦合模理论计算的结果相吻合 ,表明这是分析光纤光栅的光反射特性的一种有效的新方法 .  相似文献   
78.
后方油库整体生存概率分析计算   总被引:1,自引:1,他引:0  
针对我军后方油库特点,探讨了油库整体生存概率计算的基本思路和方法,分析了各类分项目标生存概率的计算方法,采用层次分析对后方油库各分项目标权值进行了详细分析计算,可为后方油库伪装防护效能评估提供依据。  相似文献   
79.
This paper studies a queueing system with a Markov arrival process with marked arrivals and PH‐distribution service times for each type of customer. Customers (regardless of their types) are served on a mixed first‐come‐first‐served (FCFS) and last‐come‐first‐served (LCFS) nonpreemptive basis. That is, when the queue length is N (a positive integer) or less, customers are served on an FCFS basis; otherwise, customers are served on an LCFS basis. The focus is on the stationary distribution of queue strings, busy periods, and waiting times of individual types of customers. A computational approach is developed for computing the stationary distribution of queue strings, the mean of busy period, and the means and variances of waiting times. The relationship between these performance measures and the threshold number N is analyzed in depth numerically. It is found that the variance of the virtual (actual) waiting time of an arbitrary customer can be reduced by increasing N. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 399–421, 2000  相似文献   
80.
Consider a distribution system with a central warehouse and multiple retailers. Customer demand arrives at each of the retailers continuously at a constant rate. The retailers replenish their inventories from the warehouse which in turn orders from an outside supplier with unlimited stock. There are economies of scale in replenishing the inventories at both the warehouse and the retail level. Stockouts at the retailers are backlogged. The system incurs holding and backorder costs. The objective is to minimize the long‐run average total cost in the system. This paper studies the cost effectiveness of (R, Q) policies in the above system. Under an (R, Q) policy, each facility orders a fixed quantity Q from its supplier every time its inventory position reaches a reorder point R. It is shown that (R, Q) policies are at least 76% effective. Numerical examples are provided to further illustrate the cost effectiveness of (R, Q) policies. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 422–439, 2000  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号