首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   489篇
  免费   25篇
  国内免费   2篇
  2022年   5篇
  2021年   17篇
  2019年   7篇
  2017年   11篇
  2016年   8篇
  2015年   15篇
  2014年   10篇
  2013年   72篇
  2011年   4篇
  2010年   15篇
  2009年   9篇
  2008年   5篇
  2007年   8篇
  2006年   8篇
  2005年   4篇
  2004年   6篇
  2003年   11篇
  2002年   14篇
  2001年   20篇
  2000年   5篇
  1999年   13篇
  1998年   14篇
  1997年   15篇
  1996年   9篇
  1995年   8篇
  1994年   9篇
  1993年   9篇
  1992年   7篇
  1991年   10篇
  1989年   8篇
  1988年   14篇
  1987年   6篇
  1986年   15篇
  1985年   9篇
  1984年   6篇
  1983年   5篇
  1982年   4篇
  1981年   8篇
  1980年   5篇
  1979年   11篇
  1978年   7篇
  1977年   7篇
  1975年   9篇
  1974年   7篇
  1973年   5篇
  1972年   7篇
  1971年   4篇
  1970年   4篇
  1969年   6篇
  1966年   3篇
排序方式: 共有516条查询结果,搜索用时 31 毫秒
221.
A linear programming formulation is described that will permit the optimal assignment of transportation resources (vehicles) and movement requirements to a network consisting of a set of designated origins, ports of embarkation, enroute bases, ports of debarkation, and destinations to achieve a prescribed schedule of arrivals.  相似文献   
222.
本文确定了对载车数学模型构造方法,并试图以KDM-1移动机器人作为实例,用非完整系统力学当作分析工具,通过实验获得模型数据,并由实车行驶进行检验,几个重要参数由仿真试验校核。数学模型的仿真与室内的行车试验相对比的结果比较一致。对同类载车数学模型的建立提供了有效的方法。  相似文献   
223.
本文以实验结果为依据,首先分析了塑料弹体影响弹丸膛内运动的物理性能,然后结合旋转弹丸的膛内运动特征,经过模拟试验,采用数学拟合法,初步建立旋转稳定弹塑料弹体工程设计计算的数学模型(包括结构尺寸设计计算、强度计算和内弹道计算)。  相似文献   
224.
On-site verification of ICBMs in the context of an arms control agreement might involve a situation where an inspector would choose one or more of a number of identical areas to inspect and would have confidence that the other areas had the same characteristics. This article considers optimal attack and defense of missiles deceptively based in a number of identical areas. The attacker may allocate warheads across areas as he desires and uniformly within areas. The defender may allocate interceptors across areas as he desires and either uniformly or preferentially within areas. The effect of restricting the defender to uniform allocation across areas is explored for various assumptions. Robustness of surviving missiles with respect to the number of attacking warheads is studied. Results are presented for a wide range of cases.  相似文献   
225.
A framework involving independent competing risks permits observing failures due to a specific cause and failures due to a competing cause, which constitute survival times from the cause of primary interest. Is observing more failures more informative than observing survivals? Intuitively, due to the definitiveness of failures, the answer seems to be the former. However, it has been shown before that this intuition holds when estimating the mean but not the failure rate of the exponential model with a gamma prior distribution for the failure rate. In this article, we address this question at a more general level. We show that for a certain class of distributions failures can be more informative than survivals for prediction of life length and vice versa for some others. We also show that for a large class of lifetime models, failure is less informative than survival for estimating the proportional hazards parameter with gamma, Jeffreys, and uniform priors. We further show that, for this class of lifetime models, on average, failure is more informative than survival for parameter estimation and for prediction. These results imply that the inferential purpose and properties of the lifetime distribution are germane for conducting life tests. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013  相似文献   
226.
227.
We investigate the solvability of two single‐machine scheduling problems when the objective is to identify among all job subsets with cardinality k,1≤kn, the one that has the minimum objective function value. For the single‐machine minimum maximum lateness problem, we conclude that the problem is solvable in O(n2) time using the proposed REMOVE algorithm. This algorithm can also be used as an alternative to Moore's algorithm to solve the minimum number of tardy jobs problem by actually solving the hierarchical problem in which the objective is to minimize the maximum lateness subject to the minimum number of tardy jobs. We then show that the REMOVE algorithm cannot be used to solve the general case of the single‐machine total‐weighted completion time problem; we derive sufficient conditions among the job parameters so that the total weighted completion time problem becomes solvable in O(n2) time. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 60: 449–453, 2013  相似文献   
228.
229.
230.
Charles Ted Rutledge Bohannan (1914–1982) became an integral agent of US counterinsurgency operations during the early Cold War, contributing to both the success of the COIN effort to defeat the communist Huk insurgents in the Philippines and the stalled COIN efforts in Vietnam. In the early 1960s, he wrote a short and compact analysis of the US and Filipino experience of guerrilla warfare, from the Philippine–American war until the defeat of the Huk Rebellion. It was never published. Reprinted here, Bohannan's analysis of lessons learned makes a substantial contribution to the history of American ideas of unconventional warfare by an expert who contributed these lessons to the successful defeat of an insurgency in South East Asia.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号