全文获取类型
收费全文 | 736篇 |
免费 | 24篇 |
国内免费 | 1篇 |
出版年
2021年 | 6篇 |
2019年 | 22篇 |
2018年 | 18篇 |
2017年 | 15篇 |
2016年 | 14篇 |
2015年 | 13篇 |
2014年 | 17篇 |
2013年 | 138篇 |
2012年 | 5篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2007年 | 11篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 14篇 |
1997年 | 18篇 |
1996年 | 10篇 |
1995年 | 15篇 |
1994年 | 19篇 |
1993年 | 19篇 |
1992年 | 17篇 |
1991年 | 19篇 |
1990年 | 16篇 |
1989年 | 12篇 |
1986年 | 10篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 13篇 |
1980年 | 10篇 |
1979年 | 17篇 |
1978年 | 11篇 |
1977年 | 8篇 |
1976年 | 11篇 |
1975年 | 13篇 |
1974年 | 15篇 |
1973年 | 11篇 |
1972年 | 12篇 |
1971年 | 11篇 |
1970年 | 6篇 |
1969年 | 9篇 |
1968年 | 13篇 |
1967年 | 6篇 |
1966年 | 5篇 |
排序方式: 共有761条查询结果,搜索用时 46 毫秒
691.
Computational complexity of finding Pareto efficient outcomes for biobjective lot‐sizing models 下载免费PDF全文
In this article, we study a biobjective economic lot‐sizing problem with applications, among others, in green logistics. The first objective aims to minimize the total lot‐sizing costs including production and inventory holding costs, whereas the second one minimizes the maximum production and inventory block expenditure. We derive (almost) tight complexity results for the Pareto efficient outcome problem under nonspeculative lot‐sizing costs. First, we identify nontrivial problem classes for which this problem is polynomially solvable. Second, if we relax any of the parameter assumptions, we show that (except for one case) finding a single Pareto efficient outcome is an ‐hard task in general. Finally, we shed some light on the task of describing the Pareto frontier. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 386–402, 2014 相似文献
692.
Freedom C. Onuoha 《African Security Review》2014,23(4):405-411
Trafficking in persons in Nigeria has largely targeted adults and children, particularly women and girls. Of growing concern, however, is the recent emergence and growth of sophisticated and syndicated groups involved in baby ‘factories’ and trafficking in Nigeria. This article examines the nature, actors, modus operandi and motives behind this emergent dimension of human trafficking in Nigeria. It concludes that if concerted efforts are not made to deal with the actors and dismantle the market, its profitability will embolden current actors and even encourage new entrants into the booming trade – now and in the future. 相似文献
693.
We consider a class of facility location problems with a time dimension, which requires assigning every customer to a supply facility in each of a finite number of periods. Each facility must meet all assigned customer demand in every period at a minimum cost via its production and inventory decisions. We provide exact branch‐and‐price algorithms for this class of problems and several important variants. The corresponding pricing problem takes the form of an interesting class of production planning and order selection problems. This problem class requires selecting a set of orders that maximizes profit, defined as the revenue from selected orders minus production‐planning‐related costs incurred in fulfilling the selected orders. We provide polynomial‐time dynamic programming algorithms for this class of pricing problems, as well as for generalizations thereof. Computational testing indicates the advantage of our branch‐and‐price algorithm over various approaches that use commercial software packages. These tests also highlight the significant cost savings possible from integrating location with production and inventory decisions and demonstrate that the problem is rather insensitive to forecast errors associated with the demand streams. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011 相似文献
694.
Mustapha Bouhtou Alexander Grigoriev Stan van Hoesel Anton F. van der Kraaij Frits C.R. Spieksma Marc Uetz 《海军后勤学研究》2007,54(4):411-420
We consider a pricing problem in directed, uncapacitated networks. Tariffs must be defined by an operator, the leader, for a subset of m arcs, the tariff arcs. Costs of all other arcs in the network are assumed to be given. There are n clients, the followers, and after the tariffs have been determined, the clients route their demands independent of each other on paths with minimal total cost. The problem is to find tariffs that maximize the operator's revenue. Motivated by applications in telecommunication networks, we consider a restricted version of this problem, assuming that each client utilizes at most one of the operator's tariff arcs. The problem is equivalent to pricing bridges that clients can use in order to cross a river. We prove that this problem is APX‐hard. Moreover, we analyze the effect of uniform pricing, proving that it yields both an m approximation and a (1 + lnD)‐approximation. Here, D is upper bounded by the total demand of all clients. In addition, we consider the problem under the additional restriction that the operator must not reject any of the clients. We prove that this problem does not admit approximation algorithms with any reasonable performance guarantee, unless P = NP, and we prove the existence of an n‐approximation algorithm. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
695.
A unified treatment is given for a class of discrete distributions derived by compounding a bivariate Poisson with a bivariate discrete or continuous distribution. Using generating functions a number of interesting results are obtained for probabilities, moments, cumulants, factorial moments, and factorial cumulants. Conditional distributions and regression functions are also examined. Five illustrative examples are presented in detail. © 1994 John Wiley & Sons, Inc. 相似文献
696.
In this article we apply perturbation analysis (PA), combined with conditional Monte Carlo, to obtain derivative estimators of the expected cost per period with respect to s and S, for a class of periodic review (s, S) inventory systems with full backlogging, linear holding and shortage costs, and where the arrivals of demands follow a renewal process. We first develop the general form of four different estimators of the gradient for the finite-horizon case, and prove that they are unbiased. We next consider the problem of implementing our estimators, and develop efficient methodologies for the infinite-horizon case. For the case of exponentially distributed demand interarrival times, we implement our estimators using a single sample path. Generally distributed interarrival times are modeled as phase-type distributions, and the implementation of this more general case requires a number of additional off-line simulations. The resulting estimators are still efficient and practical, provided that the number of phases is not too large. We conclude by reporting the results of simulation experiments. The results provide further validity of our methodology and also indicate that our estimators have very low variance. © 1994 John Wiley & Sons, Inc. 相似文献
697.
A centralized inventory system serves a number of stores with common ownership, and thus reliable and timely information sharing. Each of them pays a share of the inventory cost, and the reward structure leaves the owners of individual stores rewarded for their individual performance. Appropriate selection of a cost allocation method is important if such a centralized system is to last. In this work we propose three necessary criteria—stability (core of a related cooperative game), justifiability (consistency of benefits with costs), and polynomial computability. For a concrete example we demonstrate that common allocation procedures may not meet all three tests, and we present a method that that meets all three criteria. This kind of cost allocation analysis helps the common management to evaluate the trade-offs in choosing an allocation scheme for the cost of inventory centralization. © 1996 John Wiley & Sons, Inc. 相似文献
698.
699.
The minimum makespan of the general parallel machine scheduling problem with m machines and n jobs is studied. As for a number of other important combinatorial problems, the theory of empirical processes proves to be a very elegant and powerful tool for the probabilistic analysis of the solution value. It is used in this paper to derive a scheduling constant θ such that, for random processing times, the minimum makespan almost surely grows as θn when n goes to infinity. Moreover, a thorough probabilistic analysis is performed on the difference between the minimum makespan and θn. Explicit expressions for the scheduling constant are given for an arbitrary number of unrelated machines with identically distributed processing times (with an increasing failure rate), and for an arbitrary number of uniform machines and generally distributed processing times. © 1996 John Wiley & Sons, Inc. 相似文献
700.
Functional equations enable us to arrive at a simple consensus model for fatigue life of longitudinal elements based on engineering principles. The model is then applied to two representative data sets. By the application of proportional hazards techniques and subsequent likelihood analysis, simple parsimonious Weibull models are derived. Inter alia attention is given to the desirability of deriving models exhibiting plausible asymptotic independence. © 1996 John Wiley & Sons, Inc. 相似文献