全文获取类型
| 收费全文 | 1172篇 |
| 免费 | 36篇 |
| 国内免费 | 7篇 |
专业分类
| 1215篇 |
出版年
| 2025年 | 4篇 |
| 2024年 | 9篇 |
| 2023年 | 24篇 |
| 2022年 | 16篇 |
| 2021年 | 19篇 |
| 2020年 | 18篇 |
| 2019年 | 24篇 |
| 2018年 | 25篇 |
| 2017年 | 41篇 |
| 2016年 | 52篇 |
| 2015年 | 44篇 |
| 2014年 | 68篇 |
| 2013年 | 82篇 |
| 2012年 | 78篇 |
| 2011年 | 73篇 |
| 2010年 | 54篇 |
| 2009年 | 78篇 |
| 2008年 | 40篇 |
| 2007年 | 48篇 |
| 2006年 | 65篇 |
| 2005年 | 59篇 |
| 2004年 | 52篇 |
| 2003年 | 42篇 |
| 2002年 | 30篇 |
| 2001年 | 37篇 |
| 2000年 | 29篇 |
| 1999年 | 13篇 |
| 1998年 | 19篇 |
| 1997年 | 8篇 |
| 1996年 | 10篇 |
| 1995年 | 13篇 |
| 1994年 | 6篇 |
| 1993年 | 3篇 |
| 1992年 | 7篇 |
| 1991年 | 11篇 |
| 1990年 | 11篇 |
| 1989年 | 2篇 |
| 1988年 | 1篇 |
排序方式： 共有1215条查询结果，搜索用时 15 毫秒
171.
In this article, we develop a novel electric power supply chain network model with fuel supply markets that captures both the economic network transactions in energy supply markets and the physical network transmission constraints in the electric power network. The theoretical derivation and analysis are done using the theory of variational inequalities. We then apply the model to a specific case, the New England electric power supply chain, consisting of six states, five fuel types, 82 power generators, with a total of 573 generating units, and 10 demand market regions. The empirical case study demonstrates that the regional electric power prices simulated by our model match the actual electricity prices in New England very well. We also compute the electric power prices and the spark spread, an important measure of the power plant profitability, under natural gas and oil price variations. The empirical examples illustrate that in New England, the market/grid‐level fuel competition has become the major factor that affects the influence of the oil price on the natural gas price. Finally, we utilize the model to quantitatively investigate how changes in the demand for electricity influence the electric power and the fuel markets from a regional perspective. The theoretical model can be applied to other regions and multiple electricity markets under deregulation to quantify the interactions in electric power/energy supply chains and their effects on flows and prices. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009 相似文献
172.
Todas information and communication network requires a design that is secure to tampering. Traditional performance measures of reliability and throughput must be supplemented with measures of security. Recognition of an adversary who can inflict damage leads toward a game‐theoretic model. Through such a formulation, guidelines for network designs and improvements are derived. We opt for a design that is most robust to withstand both natural degradation and adversarial attacks. Extensive computational experience with such a model suggests that a Nash‐equilibrium design exists that can withstand the worst possible damage. Most important, the equilibrium is value‐free in that it is stable irrespective of the unit costs associated with reliability vs. capacity improvement and how one wishes to trade between throughput and reliability. This finding helps to pinpoint the most critical components in network design. From a policy standpoint, the model also allows the monetary value of information‐security to be imputed. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009 相似文献
173.
174.
彭玲 《中国人民武装警察部队学院学报》2007,23(12):8-11
对隧道防火涂料的组成、工作原理、生产工艺流程及技术指标等作了简要阐述,并对近年来国内外隧道防火涂料研究中存在的问题及今后的发展方向进行了探讨与展望,认为隧道防火涂料既要满足隧道防火设计的要求,又要具有较高的性价比及环保性。 相似文献
175.
Analytical resolution of search theory problems, as formalized by B.O. Koopman, may be applied with some model extension to various resource management issues. However, a fundamental prerequisite is the knowledge of the prior target density. Though this assumption has the definite advantage of simplicity, its drawback is clearly that target reactivity is not taken into account. As a preliminary step towards reactive target study stands the problem of resource planning under a min–max game context. This paper is related to Nakai's work about the game planning of resources for the detection of a stationary target. However, this initial problem is extended by adding new and more general constraints, allowing a more realistic modeling of the target and searcher behaviors. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
176.
Marco Slikker 《海军后勤学研究》2006,53(4):235-242
We study sequencing situations with a fixed initial order and linear cost functions. Cost savings can be obtained by rearranging jobs. Next to finding an optimal order, an additional issue is formed by the division of these savings. Cooperative game theory studies this issue. A common assumption states that cooperation between players is restricted to groups that are connected according to the initial order. The value of disconnected groups is defined additively over their connected components. In this paper we allow players in disconnected coalitions to switch places as long as they do not hurt the players not in the coalition under consideration. The resulting games are called relaxed sequencing games. Although they have been studied before, no general results on stable profit divisions have been derived so far. In this paper we prove that relaxed sequencing games have a nonempty core, i.e., they all have stable profit divisions. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006 相似文献
177.
为更有效地评价舰炮武器系统的射击能力和武器效能,本文以排队论为基础,建立了由舰炮武器系统与目标组成的排队系统服务概率数学模型,为综合评价舰炮武器系统的射击能力和系统效能提供参考依据。 相似文献
178.
二值化联合变换相关器识别复杂背景目标时的阈值选取 总被引：1，自引：0，他引：1
讨论了利用二值化联合变换相关器对复杂背景目标进行相关识别的阈值选取问题。由于不同阈值对二值化联合变换相关器识别结果有很大的影响,阈值过高,会损失过多的联合变换功率谱中的有效成份,使相关峰减弱;阈值过低,会使联合功率谱中的噪声放大,相关峰可能被淹没在噪声之中。因而存在一个最佳阈值。实验表明,最佳阈值位于联合功率谱最大灰度值的40%～50%之间,在此阈值范围内,相关峰值较高,噪声也得到有效抑制。 相似文献
179.
The current combat motivation model based on primary group thesis assumes that the main force behind motivation is peer-bonding or otherwise known as unit cohesion. Cohesion is perceived as an all-encompassing factor that leads to satisfactory (or unsatisfactory in lack thereof) military effectiveness and performance in conflict environments. However, the article identifies three main problems with this perspective: 1. mono-dimensional view of motivation; 2. motivation based on heteronomy, and 3. self-reporting bias. The current model does not consider motivation as a separate entity from cohesion; it does not place motivation as fundamental human value; lastly, it takes motivation as granted by-product of socialization. The article proposes a new combat motivation model based on The Self-Determination Theory. The theory maintains that human motivation requires satisfaction of three psychological needs of competence, relatedness, and autonomy. The degree of satisfaction of those three needs leads to different types of regulated motivations – a continuum from intrinsic to extrinsic – each of which has specifiable consequences for learning, performance, and well-being of an individual. 相似文献
180.
Many manufacturers sell their products through retailers and share the revenue with those retailers. Given this phenomenon, we build a stylized model to investigate the role of revenue sharing schemes in supply chain coordination and product variety decisions. In our model, a monopolistic manufacturer serves two segments of consumers, which are distinguished by their willingness to pay for quality. In the scenario with exogenous revenue sharing ratios, when the potential gain from serving the low segment is substantial (e.g., the low‐segment consumers' willingness to pay is high enough or the low segment takes a large enough proportion of the market), the retailer is better off abandoning the revenue sharing scheme. Moreover, when the potential gain from serving the low (high) segment is substantial enough, the manufacturer finds it profitable to offer a single product. Furthermore, when revenue sharing ratios are endogenous, we divide our analysis into two cases, depending on the methods of cooperation. When revenue sharing ratios are negotiated at the very beginning, the decentralized supply chain causes further distortion. This suggests that the central premise of revenue sharing—the coordination of supply chains—may be undermined if supply chain parties meticulously bargain over it. 相似文献