全文获取类型
收费全文 | 643篇 |
免费 | 5篇 |
专业分类
648篇 |
出版年
2023年 | 4篇 |
2021年 | 16篇 |
2020年 | 11篇 |
2019年 | 6篇 |
2018年 | 4篇 |
2017年 | 23篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 23篇 |
2013年 | 85篇 |
2012年 | 34篇 |
2011年 | 35篇 |
2010年 | 35篇 |
2009年 | 28篇 |
2008年 | 32篇 |
2007年 | 17篇 |
2006年 | 21篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2001年 | 4篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 12篇 |
1988年 | 3篇 |
1987年 | 10篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1979年 | 11篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1972年 | 12篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 9篇 |
1968年 | 7篇 |
1966年 | 3篇 |
排序方式: 共有648条查询结果,搜索用时 15 毫秒
131.
In this article we introduce a 2‐machine flowshop with processing flexibility. Two processing modes are available for each task: namely, processing by the designated processor, and processing simultaneously by both processors. The objective studied is makespan minimization. This production environment is encountered in repetitive manufacturing shops equipped with processors that have the flexibility to execute orders either individually or in coordination. In the latter case, the product designer exploits processing synergies between two processors so as to execute a particular task much faster than a dedicated processor. This type of flowshop environment is also encountered in labor‐intensive assembly lines where products moving downstream can be processed either in the designated assembly stations or by pulling together the work teams of adjacent stations. This scheduling problem requires determining the mode of operation of each task, and the subsequent scheduling that preserves the flowshop constraints. We show that the problem is ordinary NP‐complete and obtain an optimal solution using a dynamic programming algorithm with considerable computational requirements for medium and large problems. Then, we present a number of dynamic programming relaxations and analyze their worst‐case error performance. Finally, we present a polynomial time heuristic with worst‐case error performance comparable to that of the dynamic programming relaxations. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004. 相似文献
132.
Tobias Brueggemann Johann L. Hurink Tjark Vredeveld Gerhard J. Woeginger 《海军后勤学研究》2011,58(8):795-803
We investigate the quality of local search heuristics for the scheduling problem of minimizing the makespan on identical parallel machines. We study exponential size neighborhoods (whose size grows exponentially with the input length) that can be searched in polynomial time, and we derive worst‐case approximation guarantees for the local optima of such neighborhoods. The so‐called split neighborhood splits a feasible schedule into two layers, and then recombines the two layers by finding a perfect matching. We show that the makespan of every local optimum for split is at most a factor of 2 away from the globally optimal makespan. We then combine the split neighborhood with two neighborhoods from the literature. The combination of split with the jump neighborhood only marginally improves the approximation guarantee, whereas the combination with the lexicographic‐jump neighborhood decreases the approximation guarantee from 2 to 3/2. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011 相似文献
133.
Mathilde von Bülow Lecturer 《战略研究杂志》2013,36(4):703-729
Between 1957 and 1959 the West German company Telefunken and the Bonn government became prime targets in the French army's campaign against the Front de Libération Nationale's (FLN) efforts to establish communications networks. To the French military, the prevention of sales of Telefunken equipment to the FLN or its allies constituted a matter of strategic importance. To the Germans, it was an act of economic protectionism that exposed France's continued misgivings of Germany. The problem exerted a considerable strain between Paris and Bonn, and even threatened to harm German-Arab relations. The Telefunken affair thus highlights the Algerian war's international ramifications. It further reveals the responsibility of the French military in the internationalisation of that war. 相似文献
134.
Gerhard Kümmel 《战略研究杂志》2013,36(2):7-28
The debate on the civil–military gap and especially the TISS findings are viewed with a focus on Germany. After outlining the historical development of civil–military relations, the question of a civil–military gap is explored with data from 2001. The study finds similarities and differences in the attitudes of the civilian and the military population on several issues. Overall, there is a broad overlap of attitudes, yet differences do exist, especially on issues of foreign policy and things military. It is argued that at the beginning of the twenty-first century, civil–military relations in Germany are largely uncontested, but will become more strained. 相似文献
135.
Ordered flow shop models have appeared in the literature since the mid‐1970s and proportionate flow shop models have appeared since the early 1980s. We provide a detailed review of these models along with some analysis and potential topics for future research. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2013 相似文献
136.
137.
Although a number of studies concerning Turkish defence-growth relation have been published in recent years, little attention is given the demand for Turkish defence expenditure. This is an important issue for understanding which variables contribute to the determination of the demand for military expenditure. However, it is difficult to develop a general theory or a standard empirical approach for the determination of the demand military expenditure. This study models and estimates the demand for Turkish defence expenditure for the period 1951-1998 using autoregressive distributed lag approach to cointegration (ARDL) following the methodology outlined in Pesaran and Shin (1999). This procedure can be applied regardless of the stationary properties of the variables in the sample and allows for inferences on long-run estimates, which is not possible under alternative cointegration procedures. The findings suggest that Turkish defence spending is determined by NATO's defence spending, Greece's defence spending and some security considerations. 相似文献
138.
ABSTRACTThis study seeks to evaluate the threat of malicious chemical use by non-state actors. It finds that non-state actors have primarily turned to ready-to-use crude chemical weapons (CW) instead of traditional CW agents. Interestingly, the worst crude CW attacks have been more destructive than those employing traditional CW. Scenarios for catastrophic consequences exist, but chemical attacks have typically been used to accomplish tactical goals, which leverage psychological and economic impacts. Therefore, successful efforts to counter CW proliferation by non-state actors must be substantially different from those targeting states. 相似文献
139.
设计了四轮全向移动机器人的传感器信息采集硬件电路,并通过分析四轮全向移动机器人的运动学模型,提出了基于TI公司最新研发的TMS320F28069为主控制器的直流电机双闭环速度控制方案.试验结果表明:所提控制方案能够满足四轮全向移动机器人速度控制的要求,且响应速度快、误差小. 相似文献
140.