全文获取类型
收费全文 | 3436篇 |
免费 | 88篇 |
国内免费 | 1篇 |
出版年
2021年 | 38篇 |
2019年 | 91篇 |
2018年 | 59篇 |
2017年 | 82篇 |
2016年 | 82篇 |
2015年 | 63篇 |
2014年 | 65篇 |
2013年 | 743篇 |
2010年 | 39篇 |
2009年 | 40篇 |
2008年 | 51篇 |
2007年 | 53篇 |
2006年 | 37篇 |
2005年 | 46篇 |
2004年 | 56篇 |
2003年 | 45篇 |
2002年 | 59篇 |
1999年 | 42篇 |
1998年 | 46篇 |
1997年 | 49篇 |
1996年 | 63篇 |
1995年 | 43篇 |
1994年 | 62篇 |
1993年 | 64篇 |
1992年 | 59篇 |
1991年 | 74篇 |
1990年 | 40篇 |
1989年 | 73篇 |
1988年 | 80篇 |
1987年 | 70篇 |
1986年 | 71篇 |
1985年 | 64篇 |
1984年 | 37篇 |
1983年 | 42篇 |
1982年 | 43篇 |
1981年 | 46篇 |
1980年 | 51篇 |
1979年 | 46篇 |
1978年 | 49篇 |
1977年 | 45篇 |
1976年 | 46篇 |
1975年 | 47篇 |
1974年 | 52篇 |
1973年 | 50篇 |
1972年 | 52篇 |
1971年 | 43篇 |
1970年 | 41篇 |
1969年 | 40篇 |
1968年 | 34篇 |
1967年 | 34篇 |
排序方式: 共有3525条查询结果,搜索用时 15 毫秒
661.
In many practical manufacturing environments, jobs to be processed can be divided into different families such that a setup is required whenever there is a switch from processing a job of one family to another job of a different family. The time for setup could be sequence independent or sequence dependent. We consider two particular scheduling problems relevant to such situations. In both problems, we are given a set of jobs to be processed on a set of identical parallel machines. The objective of the first problem is to minimize total weighted completion time of jobs, and that of the second problem is to minimize weighted number of tardy jobs. We propose column generation based branch and bound exact solution algorithms for the problems. Computational experiments show that the algorithms are capable of solving both problems of medium size to optimality within reasonable computational time. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 823–840, 2003. 相似文献
662.
This paper studies capacity expansions for a production facility that faces uncertain customer demand for a single product family. The capacity of the facility is modeled in three tiers, as follows. The first tier consists of a set of upper bounds on production that correspond to different resource types (e.g., machine types, categories of manpower, etc.). These upper bounds are augmented in increments of fixed size (e.g., by purchasing machines of standard types). There is a second‐tier resource that constrains the first‐tier bounds (e.g., clean room floor space). The third‐tier resource bounds the availability of the second‐tier resource (e.g., the total floor space enclosed by the building, land, etc.). The second and third‐tier resources are expanded at various times in various amounts. The cost of capacity expansion at each tier has both fixed and proportional elements. The lost sales cost is used as a measure for the level of customer service. The paper presents a polynomial time algorithm (FIFEX) to minimize the total cost by computing optimal expansion times and amounts for all three types of capacity jointly. It accommodates positive lead times for each type. Demand is assumed to be nondecreasing in a “weak” sense. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004. 相似文献
663.
Consider a project during the life cycle of which there are cash payouts and in‐flows. To better meet his financial commitments, the project owner would like to meet all deadlines without running out of cash. We show that the cash availability objective is similar to the total weighted flowtime used to measure work‐in‐progress performance in the scheduling and inventory control literatures. In this article we provide several specialized solution methods for the problem of minimizing total weighted flowtime in an arbitrary acyclic project network, subject to activity release times and due dates, where the activity weights may be positive or negative and represent cash in‐ and out‐flows. We describe the structure of an optimal solution and provide several efficient algorithms and their complexity based on mincost and maxflow formulations. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006 相似文献
664.
Joseph Y.‐T. Leung 《海军后勤学研究》2002,49(4):422-431
We consider the problem of sequencing n jobs on a single machine, with each job having a processing time and a common due date. The common due date is assumed to be so large that all jobs can complete by the due date. It is known that there is an O(n log n)‐time algorithm for finding a schedule with minimum total earliness and tardiness. In this article, we consider finding a schedule with dual criteria. The primary goal is to minimize the total earliness and tardiness. The secondary goals are to minimize: (1) the maximum earliness and tardiness; (2) the sum of the maximum of the squares of earliness and tardiness; (3) the sum of the squares of earliness and tardiness. For the first two criteria, we show that the problems are NP‐hard and we give a fully polynomial time approximation scheme for both of them. For the last two criteria, we show that the ratio of the worst schedule versus the best schedule is no more than . © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 422–431, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10020 相似文献
665.
Frederic M. Wehrey 《Small Wars & Insurgencies》2013,24(3):53-74
This article analyzes Hizballah's war against Israel in south Lebanon as a psychological contest where public opinion, perception, and persuasion were the real determinants of victory. Hizballah successfully mobilized popular support for its war by communicating nationalist and religious themes to different sectarian groups in Lebanon. At the same time, it used classic guerrilla warfare as a carefully calibrated psychological tool to erode the morale of Israeli forces, their Lebanese allies, and the Israeli public's support for the war. Hizballah's sophisticated media capability, particularly combat video footage aired on its satellite TV station and the Internet, played a critical role in amplifying the effects of its attrition campaign. By orchestrating information-age media and guerrilla tactics, this strategy has important implications for the future of irregular warfare. 相似文献
666.
Multi-echelon logistic systems are essential parts of the service support function of high technology firms. The combination of technological developments and competitive pressures has led to the development of services systems with a unique set of characteristics. These characteristics include (1) low demand probabilities: (2) high cost items; (3) complex echelon structures; (4) existence of pooling mechanisms among stocking locations at the same echelon level; (5) high priority for service, which is often expressed in terms of response time service levels for product groups of items: (6) scrapping of failed parts; and (7) recycling of issued stock due to diagnostic use. This article develops a comprehensive model of a stochastic, multi-echelon inventory system that takes account of the above characteristics. Solutions to the constrained optimization problem are found using a branch and bound procedure. The results of applying this procedure to a spare parts inventory system for a computer manufacturer have led to a number of important policy conclusions. 相似文献
667.
668.
This article presents a branch and bound method for solving the problem of minimizing a separable concave function over a convex polyhedral set where the variables are restricted to be integer valued. Computational results are reported. 相似文献
669.
This paper provides a framework in which warranty policies for non-repairable items can be evaluated according to risk preferences of both buyers and sellers. In particular, a warranty price schedule is established such that sellers are indifferent among the policies. Given this schedule, a buyer's response is expressed by selecting the price-warranty combination that minimizes disutility. Within this framework, a warranty can be viewed as an instrumet of risk management that can induce more sales and greater profitability. For given utility functions, analytical results for the development of a price schedule are developed. Numerical results illustrate the substitution effects between warranty terms, prices, and risk parameters. 相似文献
670.
Consider a fleet of vehicles comprised of K1 identical tankers and K2 identical nontankers (small aircraft). Tankers are capable of refueling other tankers as well as nontankers. The problem is to find that refueling sequence of the tankers that maximizes the range simultaneously attainable by all K2 nontankers. A recent paper established that the “unit refueling sequence,” comprised of one tanker refueling at each of K1 refueling operations, is optimal. The same paper also proffered the following conjecture for the case that the number of refueling operations is constrained to be less than the number of tankers: A nonincreasing refueling sequence is optimal. This article proves the conjecture. 相似文献