全文获取类型
收费全文 | 231篇 |
免费 | 52篇 |
国内免费 | 5篇 |
出版年
2022年 | 3篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 12篇 |
2012年 | 18篇 |
2011年 | 17篇 |
2010年 | 14篇 |
2009年 | 17篇 |
2008年 | 18篇 |
2007年 | 21篇 |
2006年 | 18篇 |
2005年 | 11篇 |
2004年 | 18篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
排序方式: 共有288条查询结果,搜索用时 437 毫秒
161.
徐盟菊 《中国人民武装警察部队学院学报》2011,(6):59-61
针对贵州省商贸城商业用房的消防安全管理工作现状的分析,提出以"防火墙"工作建设为契机,加大对商贸城商业用房的消防安全管理力度,使此项重而难的工作逐步走向良好轨道,避免出现重大火灾事故,为构建和谐社会奠定良好基础。 相似文献
162.
This article presents a flexible days‐on and days‐off scheduling problem and develops an exact branch and price (B&P) algorithm to find solutions. The main objective is to minimize the size of the total workforce required to cover time‐varying demand over a planning horizon that may extend up to 12 weeks. A new aspect of the problem is the general restriction that the number of consecutive days on and the number of consecutive days off must each fall within a predefined range. Moreover, the total assignment of working days in the planning horizon cannot exceed some maximum value. In the B&P framework, the master problem is stated as a set covering‐type problem whose columns are generated iteratively by solving one of three different subproblems. The first is an implicit model, the second is a resource constrained shortest path problem, and the third is a dynamic program. Computational experiments using both real‐word and randomly generated data show that workforce reductions up to 66% are possible with highly flexible days‐on and days‐off patterns. When evaluating the performance of the three subproblems, it was found that each yielded equivalent solutions but the dynamic program proved to be significantly more efficient. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 60: 678–701, 2013 相似文献
163.
We study a knapsack problem with an additional minimum filling constraint, such that the total weight of selected items cannot be less than a given threshold. The problem has several applications in shipping, e‐commerce, and transportation service procurement. When the threshold equals the knapsack capacity, even finding a feasible solution to the problem is NP‐hard. Therefore, we consider the case when the ratio α of threshold to capacity is less than 1. For this case, we develop an approximation scheme that returns a feasible solution with a total profit not less than (1 ‐ ε) times the total profit of an optimal solution for any ε > 0, and with a running time polynomial in the number of items, 1/ε, and 1/(1‐α). © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2013 相似文献
164.
165.
166.
本文对瓶颈指派问题给出了一种新的算法,该算法不需要利用最大流算法,而类似于解经典指派问题的匈牙利算法。该算法是一个多项式时间算法,其复杂性为O(n3) 相似文献
167.
Testing provides essential information for managing infectious disease outbreaks, such as the COVID-19 pandemic. When testing resources are scarce, an important managerial decision is who to test. This decision is compounded by the fact that potential testing subjects are heterogeneous in multiple dimensions that are important to consider, including their likelihood of being disease-positive, and how much potential harm would be averted through testing and the subsequent interventions. To increase testing coverage, pooled testing can be utilized, but this comes at a cost of increased false-negatives when the test is imperfect. Then, the decision problem is to partition the heterogeneous testing population into three mutually exclusive sets: those to be individually tested, those to be pool tested, and those not to be tested. Additionally, the subjects to be pool tested must be further partitioned into testing pools, potentially containing different numbers of subjects. The objectives include the minimization of harm (through detection and mitigation) or maximization of testing coverage. We develop data-driven optimization models and algorithms to design pooled testing strategies, and show, via a COVID-19 contact tracing case study, that the proposed testing strategies can substantially outperform the current practice used for COVID-19 contact tracing (individually testing those contacts with symptoms). Our results demonstrate the substantial benefits of optimizing the testing design, while considering the multiple dimensions of population heterogeneity and the limited testing capacity. 相似文献
168.
169.
章瑞春 《中国人民武装警察部队学院学报》2014,(2):72-73
2009年《消防法》实施以来,消防工作得到了长足的发展,但也反映出一定的问题。分析了《消防法》实施几年来在执法主体力量、概念界定、法律术语等方面中存在的问题,认为应通过合理考虑执法力量状况、理性看待法律条文本身、主动形成执法合作意识等措施,更好地发挥《消防法》在消防监督管理中的重要作用。 相似文献
170.
在频率步进高分辨ISAR成像中,目标的径向运动会带来距离多普勒耦合,从而对ISAR图像有较大的影响。提出了一种基于图像对比度最优的运动参数估计方法。该法分析了径向速度和径向加速度对多普勒像对比度函数的影响。通过构造相位补偿因子,在多普勒像中基于多普勒像对比度最优估计径向加速度。在径向加速度补偿后,在距离像中基于距离像对比度最优估计径向速度。进行运动补偿,利用RD算法实现了目标的高分辨ISAR成像。该方法具有运动参数估计精度高和计算量小的优点。仿真结果验证了方法的有效性。 相似文献