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   493篇
  免费   14篇
  2021年   5篇
  2019年   12篇
  2018年   10篇
  2017年   12篇
  2016年   7篇
  2015年   8篇
  2014年   9篇
  2013年   115篇
  2011年   5篇
  2010年   7篇
  2009年   7篇
  2008年   10篇
  2006年   7篇
  2005年   10篇
  2004年   9篇
  2003年   6篇
  2002年   6篇
  2001年   5篇
  2000年   6篇
  1998年   7篇
  1997年   5篇
  1996年   12篇
  1995年   8篇
  1994年   6篇
  1993年   8篇
  1992年   12篇
  1991年   11篇
  1990年   7篇
  1989年   10篇
  1988年   11篇
  1987年   11篇
  1986年   9篇
  1985年   8篇
  1984年   7篇
  1983年   4篇
  1982年   4篇
  1981年   8篇
  1980年   14篇
  1979年   6篇
  1978年   6篇
  1977年   5篇
  1976年   5篇
  1975年   9篇
  1974年   4篇
  1971年   9篇
  1970年   5篇
  1969年   4篇
  1968年   5篇
  1967年   5篇
  1966年   7篇
排序方式: 共有507条查询结果,搜索用时 15 毫秒
311.
The March 2012 coup in Mali opened the door to expanded territorial occupation in northern Mali by Tuareg separatists and subsequently armed Islamist extremists. French forces intervened at the behest of the interim government in Mali. This article examines how various actors frame the conflict to their advantage. While the Malian government and France are allies, the position of various Tuareg actors shift over time as they strategize and weigh the value of allegiance with the French. Local extremist organizations are labeled as terrorists and are targeted as enemies. This article argues that the conflict has been decontextualized and framed within the ‘war on terror’. France’s decision to intervene and to expand their regional military presence, rather than exit, is legitimized by the framing of their intervention as integral to counterterrorism efforts.  相似文献   
312.
We consider a class of production scheduling models with m identical machines in parallel and k different product types. It takes a time pi to produce one unit of product type i on any one of the machines. There is a demand stream for product type i consisting of ni units with each unit having a given due date. Before a machine starts with the production of a batch of products of type i a setup cost c is incurred. We consider several different objective functions. Each one of the objective functions has three components, namely a total setup cost, a total earliness cost, and a total tardiness cost. In our class of problems we find a relatively large number of problems that can be solved either in polynomial time or in pseudo‐polynomial time. The polynomiality or pseudo‐polynomiality is achieved under certain special conditions that may be of practical interest; for example, a regularity pattern in the string of due dates combined with earliness and tardiness costs that are similar for different types of products. The class of models we consider includes as special cases discrete counterparts of a number of inventory models that have been considered in the literature before, e.g., Wagner and Whitin (Manage Sci 5 (1958), 89–96) and Zangwill (Oper Res 14 (1966), 486–507; Manage Sci 15 (1969), 506–527). © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008  相似文献   
313.
We consider a supply chain in which a retailer faces a stochastic demand, incurs backorder and inventory holding costs and uses a periodic review system to place orders from a manufacturer. The manufacturer must fill the entire order. The manufacturer incurs costs of overtime and undertime if the order deviates from the planned production capacity. We determine the optimal capacity for the manufacturer in case there is no coordination with the retailer as well as in case there is full coordination with the retailer. When there is no coordination the optimal capacity for the manufacturer is found by solving a newsvendor problem. When there is coordination, we present a dynamic programming formulation and establish that the optimal ordering policy for the retailer is characterized by two parameters. The optimal coordinated capacity for the manufacturer can then be obtained by solving a nonlinear programming problem. We present an efficient exact algorithm and a heuristic algorithm for computing the manufacturer's capacity. We discuss the impact of coordination on the supply chain cost as well as on the manufacturer's capacity. We also identify the situations in which coordination is most beneficial. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008  相似文献   
314.
A single server is faced with a collection of jobs of varying duration and urgency. Each job has a random lifetime during which it is available for nonpreemptive service. Should a job's lifetime expire before its service begins then it is lost from the system unserved. The goal is to schedule the jobs for service to maximize the expected number served to completion. Two heuristics have been proposed in the literature. One (labeled πS) operates a static priority among the job classes and works well in a “no premature job loss” limit, whereas the second (πM) is a myopic heuristic which works well when lifetimes are short. Both can exhibit poor performance for problems at some distance from the regimes for which they were designed. We develop a robustly good heuristic by an approximative approach to the application of a policy improvement step to the asymptotically optimal heuristic πS, in which we use a fluid model to obtain an approximation for the value function of πS. The performance of the proposed heuristic is investigated in an extensive numerical study. © 2010 Wiley Periodicals, Inc. Naval Research Logistics 2010  相似文献   
315.
Lot splitting is a new approach for improving productivity by dividing production lots into sublots. This approach enables accelerating production flow, reducing lead‐time and increasing the utilization of organization resources. Most of the lot splitting models in the literature have addressed a single objective problem, usually the makespan or flowtime objectives. Simultaneous minimization of these two objectives has rarely been addressed in the literature despite of its high relevancy to most industrial environments. This work aims at solving a multiobjective lot splitting problem for multiple products in a flowshop environment. Tight mixed‐integer linear programming (MILP) formulations for minimizing the makespan and flowtime are presented. Then, the MinMax solution, which takes both objectives into consideration, is defined and suggested as an alternative objective. By solving the MILP model, it was found that minimizing one objective results in an average loss of about 15% in the other objective. The MinMax solution, on the other hand, results in an average loss of 4.6% from the furthest objective and 2.5% from the closest objective. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010  相似文献   
316.
317.
318.
319.
320.
With relations with the Soviet Union growing ever ‘hotter’, it became essential for the British to comprehend Soviet atomic development. However, British intelligence had to rely on more overt methods of intelligence collection, which provided an inadequate basis from which to proceed. This was further hindered by the interpretation of such information on the basis of Anglo-American development and by the 1946 McMahon Act. Accordingly the first Soviet atomic bomb in August 1949 was not accurately predicted by the British. Meanwhile British war planning centred on the year 1957, based – it was argued – on strategic forecasts. Yet the impact of recently released intelligence material throws this into question, and instead reveals that the date reflected British war readiness, rather than when British intelligence predicted the Soviet Union would have achieved the nuclear capability to wage a successful war.  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