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   194篇
  免费   1篇
  国内免费   5篇
教育   129篇
科学研究   51篇
体育   6篇
综合类   10篇
文化理论   1篇
信息传播   3篇
  2020年   3篇
  2017年   1篇
  2015年   5篇
  2014年   14篇
  2013年   9篇
  2011年   8篇
  2010年   9篇
  2009年   15篇
  2008年   19篇
  2007年   16篇
  2006年   15篇
  2005年   17篇
  2004年   22篇
  2003年   14篇
  2002年   13篇
  2001年   5篇
  2000年   2篇
  1999年   5篇
  1998年   3篇
  1997年   2篇
  1996年   2篇
  1993年   1篇
排序方式: 共有200条查询结果,搜索用时 15 毫秒
11.
ABSTRACT

Many museums are housed in historic buildings, sometimes the building itself is part of the museum collection. Creating a stable environment by providing a nearly constant temperature and relative humidity at correct levels decreases the risk of object degradation. Maintaining this steady indoor environment, however, increases energy consumption and risks to the historic building. Museum display cases offer a solution to the mitigation of risks to which valuable objects may be subjected by providing an extra layer of protection to indoor climate fluctuations. The Anne Frank House is a historic house museum located in Amsterdam. The museum has undergone several renovations in the last years to deal with an increase in the number of visitors to over 1.2 million a year. The original diaries and other documents of Anne Frank are permanently on display in the Anne Frank House. With the recent refurbishment the possibility arose to design a new state-of-the-art display case. This study presents the results of the experimental research related to the design, performed in-situ. The temperature and relative humidity in the new exhibition space and inside the new display cases were monitored to gain insight into the hygrothermal behavior of these controlled environments. A complementary numerical study was performed to investigate effects of dynamic climate control of the exhibition gallery and climate conditions in the display case under various circumstances. Four main conclusions are presented in this paper. The investigated display case design is able to provide a stable relative humidity environment by means of silica gel, while using an active box-in-box climate control system to create stable temperature conditions. The inner case temperature depends on the temperature supplied by the display case air handling unit. Protocols must be in place in case of malfunction or failure of the climate control system of the display case. The air handling unit of the case needs to be shut off to create a passive environment for the objects on display until necessary actions are taken. Exhibition gallery set points can be less stringent when susceptible museum objects are on display in the display case. The environments are separated and provide an opportunity for energy saving set point strategies. The last conclusion drawn is that the numerical study provides valuable insight into imposing dynamic control of set points for temperature and relative humidity in the exhibition gallery and the effect on the display case environment.  相似文献   
12.
以安定操作行为稳定股价和人为干预市场的两面性作为切入点,介绍超额配售选择权的运行机制,解释该机制在保证安定操作发挥正面作用、防止产生操纵市场的后果等方面所具有的制度优势。结合超额配售选择权机制在我国的发展现状,建议协调相关法律法规的衔接。同时提出:在股票破发的情况下,投资者应当按照市场价格取得认购股票。  相似文献   
13.
The design problem of delay-dependent robust control For uncertain discrete singular systems with time-varying delay is addressed in this paper. The uncertainty is assumed to be norm-bounded. By establishing a finite sum inequality based on quadratic terms, a new delay-dependent robust stability condition is derived and expressed in terms of linear matrix inequalities (LMIs). A suitable robust state feedback control law is presented, which guarantees that the resultant closed-loop system is regular, causal and stable for all admissible uncertainties. Numerical examples are given to demonstrate the applicability of the proposed method.  相似文献   
14.
Based on input-output approach, the robust stability and stabilization problems for uncertain singular systemswith time-varying delays are investigated. The parameter uncertainties are assumed to be norm-bounded and the time-varying delays include both discrete delay and distributed delay. By introducing a new input-output model, the time-delay system is embedded in a family of systems with a forward system without time delay and a dynamical feedback uncertainty. A sufficient and necessary condition, which guarantees the system regular, impulse-free and stable for all admissible uncertainties, is obtained. Based on the strict linear matrix inequality, the desired robust state feedback controller is also obtained. Finally, a numerical example is provided to demonstrate the application of the proposed method.  相似文献   
15.
SLAM is one of the most important components in robot navigation. A SLAM algorithm based on image sequences captured by a single digital camera is proposed in this paper. By this algorithm, SIFT feature points are selected and matched between image pairs sequentially. After three images have been captured, the environment's 3D map and the camera's positions are initialized based on matched feature points and intrinsic parameters of the camera. A robust method is applied to estimate the position and orientation of the camera in the forthcoming images. Finally, a robust adaptive bundle adjustment algorithm is adopted to optimize the environment's 3D map and the camera's positions simultaneously. Results of quantitative and qualitative experiments show that our algorithm can reconstruct the environment and localize the camera accurately and efficiently.  相似文献   
16.
17.
Multi-objective robust state-feedback controller synthesis problems for linear discrete-time uncertain systems are addressed. Based on parameter-dependent Lyapunov functions, the Gl2 and GH2 norm expressed in terms of LMI (Linear Matrix Inequality) characterizations are further generalized to cope with the robust analysis for convex polytopic uncertain system. Robust state-feedback controller synthesis conditions are also derived for this class of uncertain systems. Using the above results, multi-objective state-feedback controller synthesis procedures which involve the LMI optimization technique are developed and less conservative than the existing one. An illustrative example verified the validity of the approach.  相似文献   
18.
进行“共产党员先进性教育”,对于战斗在政法一线的同志们来讲,就是要深入学习理论,立足于实践,正确处理好改革发展稳定的关系,为构建和谐社会,采取有力措施惩治犯罪、保社会稳定和人民平安,造福于社会经济的可持续发展。  相似文献   
19.
政治社会化与政治稳定   总被引:3,自引:0,他引:3  
实现并保持政治稳定是我国社会主义现代化建设过程中带来战略性和全局性的问题。政治社会化对于保持社会政治稳定有着重要作用:只有通过政治社会化,才能使我国公民形成社会主义的政治信念,确立正确的政治方向,使社会个体的发展与社会发展相一致;只有提高政治社会化的水平,才能以邓小平理论为核心内容的主流政治化深入人心,有效抵制非主流政治化对政治稳定的消极影响;通过政治社会化,不断增强公民的民主意识和法制观念,使公民掌握参与政治的实实在在的知识技能,从而有效促进权力运行和公民政治参与的规范化,有序化。  相似文献   
20.
以A省H职院为例考察高职院校执行国家高职教育变革型政策的过程,发现高职院校层次的政策执行主要受合法性机制、资源依赖机制和平稳机制的影响,前两种机制直接来自于高职院校与外部环境的关系,来自于基本体制对变革的要求;后者虽产生于高校内部环境,实际上仍是基本体制演变逻辑在校园环境中的内化。高职院校真正的变革很大程度上是学校有机的自我演进和自我发展的过程,内外机制的脱节、基本体制中变革与稳定的关系是高职院校改革表面上轰轰烈烈,内部却踯躅难行的根源。  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