全文获取类型
收费全文 | 1384篇 |
免费 | 326篇 |
国内免费 | 127篇 |
专业分类
1837篇 |
出版年
2024年 | 8篇 |
2023年 | 10篇 |
2022年 | 15篇 |
2021年 | 19篇 |
2020年 | 19篇 |
2019年 | 26篇 |
2018年 | 24篇 |
2017年 | 69篇 |
2016年 | 81篇 |
2015年 | 43篇 |
2014年 | 108篇 |
2013年 | 91篇 |
2012年 | 112篇 |
2011年 | 102篇 |
2010年 | 72篇 |
2009年 | 115篇 |
2008年 | 89篇 |
2007年 | 73篇 |
2006年 | 75篇 |
2005年 | 86篇 |
2004年 | 84篇 |
2003年 | 69篇 |
2002年 | 59篇 |
2001年 | 52篇 |
2000年 | 49篇 |
1999年 | 39篇 |
1998年 | 36篇 |
1997年 | 40篇 |
1996年 | 31篇 |
1995年 | 23篇 |
1994年 | 30篇 |
1993年 | 28篇 |
1992年 | 21篇 |
1991年 | 25篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 2篇 |
排序方式: 共有1837条查询结果,搜索用时 0 毫秒
81.
作为公安消防机构的一种相对自由的判断权和选择权,消防行政自由裁量权必须受到有效控制,并在法律规定的范围内合法、合理行使,以确保公安消防机构能够更好的承担起维护社会稳定、保卫人民生命财产安全的神圣职责。根据消防行政自由裁量权的类型及特征,分析了滥用消防行政自由裁量权的表现形式及危害,并结合当前消防工作的形势与要求,阐述了完善我国消防行政自由裁量权的控制策略。 相似文献
82.
船舶航向非线性系统离散变结构控制 总被引:1,自引:0,他引:1
基于非线性模型研究船舶航向自动舵的离散变结构控制设计问题。通过状态反馈精确线性化方法设计了二次型最优滑模面,采用离散趋近律方法求得变结构控制律。研究结果表明,所设计的离散变结构控制器能够快速准确地跟踪设定航向,并对参数摄动和外界风浪干扰具有很强的鲁棒性。 相似文献
83.
线性模型跟随控制是一种传统的控制方法,通过对增益的调整,使实际受控系统的输出跟随参考模型的输出,以达到理想的静态、动态特性。将线性模型跟随控制引入自修复飞行控制系统的重构控制中,针对发生舵面故障的飞行控制系统,设计模型跟随控制律,给出仿真实例。结果表明,该方法具有可行性和有效性。 相似文献
84.
This paper proposes a kurtosis correction (KC) method for constructing the X? and R control charts for symmetrical long‐tailed (leptokurtic) distributions. The control charts are similar to the Shewhart control charts and are very easy to use. The control limits are derived based on the degree of kurtosis estimated from the actual (subgroup) data. It is assumed that the underlying quality characteristic is symmetrically distributed and no other distributional and/or parameter assumptions are made. The control chart constants are tabulated and the performance of these charts is compared with that of the Shewhart control charts. For the case of the logistic distribution, the exact control limits are derived and are compared with the KC method and the Shewhart method. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
85.
关于独立学院教学体制的构建 总被引:1,自引:1,他引:1
独立学院作为一种新型的办学模式,是高教改革的战略抉择,对我国高等教育向“大众化教育”转变具有重要的意义。构建合理的独立学院教学体制是实现人才培养的关键。对此,独立学院必须以培养应用型专门人才为目标,以市场为导向,科学确定学生的知识结构和能力体系,构建合理的人才培养模式;应根据独立学院的特点,以教学运行管理为重点,加强教学管理的规范化建设,构建合理的教学管理机制;以提高教学质量为目标,构建合理的教学质量监控与保障体系;充分运用独立学院灵活的办学机制,构建一支由母体高校教师、专任教师和兼职教师三部分组成的,适应独立学院教学工作需要的教师队伍。 相似文献
86.
87.
介绍了双DSP技术在无线分组网络路由控制器中的应用,阐述了双DSP间通信方案的选择及双DSP系统的实现,提出了一种双DSP对多个串行通信控制器(SCC)的设计方案,并给出了具体的硬件、软件设计方法. 相似文献
88.
In this paper, we present an optimization model for coordinating inventory and transportation decisions at an outbound distribution warehouse that serves a group of customers located in a given market area. For the practical problems which motivated this paper, the warehouse is operated by a third party logistics provider. However, the models developed here may be applicable in a more general context where outbound distribution is managed by another supply chain member, e.g., a manufacturer. We consider the case where the aggregate demand of the market area is constant and known per period (e.g., per day). Under an immediate delivery policy, an outbound shipment is released each time a demand is realized (e.g., on a daily basis). On the other hand, if these shipments are consolidated over time, then larger (hence more economical) outbound freight quantities can be dispatched. In this case, the physical inventory requirements at the third party warehouse (TPW) are determined by the consolidated freight quantities. Thus, stock replenishment and outbound shipment release policies should be coordinated. By optimizing inventory and freight consolidation decisions simultaneously, we compute the parameters of an integrated inventory/outbound transportation policy. These parameters determine: (i) how often to dispatch a truck so that transportation scale economies are realized and timely delivery requirements are met, and (ii) how often, and in what quantities, the stock should be replenished at the TPW. We prove that the optimal shipment release timing policy is nonstationary, and we present algorithms for computing the policy parameters for both the uncapacitated and finite cargo capacity problems. The model presented in this study is considerably different from the existing inventory/transportation models in the literature. The classical inventory literature assumes that demands should be satisfied as they arrive so that outbound shipment costs are sunk costs, or else these costs are covered by the customer. Hence, the classical literature does not model outbound transportation costs. However, if a freight consolidation policy is in place then the outbound transportation costs can no longer be ignored in optimization. Relying on this observation, this paper models outbound transportation costs, freight consolidation decisions, and cargo capacity constraints explicitly. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 531–556, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10030 相似文献
89.
90.
基于反馈线性化的飞行器姿态运动的变结构控制方法研究 总被引:4,自引:0,他引:4
利用反馈线性化方法对飞行器姿态运动的非线性耦合进行了解耦,并对得到的线性化系统进行了变结构姿态控制系统设计,该控制系统具有优良的控制品质和鲁棒性。数字仿真结果进一步证实该方法的有效性。 相似文献