全文获取类型
收费全文 | 184篇 |
免费 | 61篇 |
国内免费 | 11篇 |
出版年
2024年 | 2篇 |
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 3篇 |
2014年 | 13篇 |
2013年 | 14篇 |
2012年 | 22篇 |
2011年 | 21篇 |
2010年 | 7篇 |
2009年 | 10篇 |
2008年 | 11篇 |
2007年 | 14篇 |
2006年 | 15篇 |
2005年 | 10篇 |
2004年 | 16篇 |
2003年 | 8篇 |
2002年 | 3篇 |
2001年 | 9篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
排序方式: 共有256条查询结果,搜索用时 15 毫秒
221.
222.
通过研究椭圆曲线群,给出基于其上的2个零知识证明方案,这2个方案均使得甲方向乙方宣称自己拥有某种信息,并通过互动证明使其确信具有该信息,但同时还未泄漏该信息。 相似文献
223.
A natural extension of the bucket brigade model of manufacturing is capable of chaotic behavior in which the product intercompletion times are, in effect, random, even though the model is completely deterministic. This is, we believe, the first proven instance of chaos in discrete manufacturing. Chaotic behavior represents a new challenge to the traditional tools of engineering management to reduce variability in production lines. Fortunately, if configured correctly, a bucket brigade assembly line can avoid such pathologies. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009 相似文献
224.
赵理莉 《国防科技大学学报》2017,39(6)
对宫颈细胞多分类,可以自动识别出不同状态的细胞,进而为宫颈癌诊断提供科学依据。在用6种多分类算法实验后,选取支持向量机(SVM)作为基分类器,先用一对一策略(one- versus -one)训练6个分类器进行3分类,然后再训练1个2分类器,这种二层4分类方法提高了识别准确率。又考虑不同层特征模式的差异性,在保证识别性能同时,每层分类前先采用主成分分析(PCA)法将原始154维特征变换到低维空间,去除冗余特征,加快识别速度。实验证明,所提层次PCA法在宫颈细胞分类中相比6种传统多分类方法有更高的识别准确率,可达90%以上;识别速度也较普通层次法提升了21.31%。 相似文献
225.
Capacity providers such as airlines often sell the same capacity to different market segments at different prices to improve their expected revenues. The absence of a secondary market, due to the nontransferability of airline tickets, gives rise to an opportunity for airlines to broker capacity between consumers with different willingness to pay. One way to broker capacity is by the introduction of callable products. The idea is similar to callable bonds where the issuer has the right, but not the obligation, to buy back the bonds at a certain price by a certain date. The idea of callable products was introduced before under the assumption that the fare-class demands are all independent. The independent assumption becomes untenable when there is significant demand recovery (respectively, demand cannibalization) when lower fares are closed (respectively, opened). In this case, consumer choice behavior should be modeled explicitly to make meaningful decisions. In this paper, we consider a general consumer choice model and develop the optimal strategy for callable products. Our numerical study illustrates how callable products are win-win-win, for the capacity provider and for both high and low fare consumers. Our studies also identify conditions for callable products to result in significant improvements in expected revenues. 相似文献
226.
227.
推进院校教育教学转型是新形势下新的课题,也是一项复杂的系统工程。到底“怎么转”、“转什么”,是关系院校建设发展一个重大而现实的课题。从确立转型理念、把握转型规律、聚合转型力量三个方面进行了探析和阐述,力求为推进转型发展提供借鉴与参考。 相似文献
228.
AbstractThis study investigates the association between defense and health spending using multi-resolution analysis incorporating the structural change model. Our empirical results suggested that a negative correlation between defense and health spending persists over the entire period of 1941–2013 in the very long-run (over 16 years cycle), but there is a change in correlation between defense and health spending in the short-run (2–4 years cycle), medium-run (4–8 years cycle), and long-run (8–16 years cycle) during the same period. In particular, there appears to have been a trade-off relationship between defense and health spending during the ex-Korean War period, but there was a complementary relationship between defense and health spending during the post-Korean War period. The crowding-out effect of health spending on defense spending during the period when the Affordable Care Act was put into effect relies on the strength of the positive correlation in the long-run (8–16 years cycle) and negative correlation in the short-run (2–4 years cycle) and very long-run (over 16 years cycle). 相似文献
229.
Consider a set of product variants that are differentiated by some secondary attributes such as flavor, color, or size. The retailer's problem is to jointly determine the set of variants to include in her product line (“assortment”), together with their prices and inventory levels, so as to maximize her expected profit. We model the consumer choice process using a multinomial logit choice model and consider a newsvendor type inventory setting. We derive the structure of the optimal assortment for some important special cases, including the case of horizontally differentiated items, and propose a dominance relationship for the general case that simplifies the search for an optimal assortment. We also discuss structural properties of the optimal prices. Finally, motivated by our analytical results, we propose a heuristic solution procedure, which is shown to be quite effective through a numerical study. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
230.
针对舰船维修具有的异质性特点导致“纯样本匹配法”并不适用于舰船维修价格指数编制的问题,首先提出采用特征价格理论,选取舰船维修特征属性并给出了量化处理原则;然后,利用合并数据特征价格建模方法,建立了舰船维修线性Hedonic价格指数模型,并针对线性模型拟合精度不高等问题,通过多种形式的Box-Cox转换,构建了舰船维修的非线性Hedonic价格指数模型,得出了舰船维修Hedonic价格指数,以反映舰船维修的“纯价格变化”趋势.最后,与通过“纯样本匹配法”获取的价格指数进行比较,并解释了二者的差异性. 相似文献