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   50篇
  免费   3篇
  国内免费   2篇
安全科学   21篇
环保管理   2篇
综合类   17篇
基础理论   11篇
评价与监测   2篇
社会与环境   1篇
灾害及防治   1篇
  2022年   1篇
  2021年   5篇
  2020年   4篇
  2019年   3篇
  2018年   1篇
  2017年   4篇
  2016年   2篇
  2015年   2篇
  2014年   2篇
  2013年   4篇
  2012年   1篇
  2011年   3篇
  2010年   2篇
  2009年   1篇
  2008年   6篇
  2007年   4篇
  2005年   1篇
  2003年   1篇
  2002年   2篇
  2001年   1篇
  2000年   3篇
  1999年   1篇
  1997年   1篇
排序方式: 共有55条查询结果,搜索用时 31 毫秒
21.
Research has long recognized the potential benefits of vision communicated at all levels of organizations. Despite this recognition, our understanding of the dynamics surrounding suborganizational visions remains limited. In this paper, we aim to explore these dynamics by investigating the role of organizational structure in the use of suborganizational visions. Although research has begun exploring the implications of structure for vision, it has done so on a limited basis in the context of vertical hierarchies. We take a more comprehensive view, exploring the role of both vertical and horizontal dimensions of structure, with specific interest in the relationship between organizational and suborganizational visions. Our findings suggest not only that structural distance moderates the relationship between organizational and suborganizational visions but also that horizontal distance from the organizational core provides the conditions under which suborganizational units communicate distinct visions that are decoupled from the organizational vision. Furthermore, we find a series of coordinating mechanisms that serve to encourage both the vertical nesting and horizontal complementarity of visions, ensuring alignment, even in the presence of decoupling from the organizational vision. Finally, in describing these findings, we elucidate the role of institutions in both providing content for and ensuring the complementarity of suborganizational visions.  相似文献   
22.
景观影响评价技术   总被引:17,自引:0,他引:17       下载免费PDF全文
首先介绍了国内外景观影响评价的一些发展和意义,提出了景观影响评价的基本概念、步骤和方法针对景观影响评价的特点,介绍了透视图法、叠图法、制作模型法和计算机显像法4种景观影响预测的手段最后针对我国景观影响评价的现状提出了一些加强和改善的建议:从环境影响评价要求上突出景观影响评价的地位;加强景观影响评价技术方法的研究;注重景观影响评价专业人员的培训.  相似文献   
23.
生物视觉的研究   总被引:3,自引:0,他引:3  
生物视觉是目前科学技术研究的热点之一。笔者通过对生物视觉形态学方面的深入研究 ,探讨了生物视觉产生、发展的结构与机制 ,尤其研讨了视觉通路的解剖结构、感受野分层等级假设、视觉信息的并行处理性质及视觉皮层间的反馈和整合作用等。同时还介绍了当前生物视觉方面的研究进展  相似文献   
24.
建筑业作为高风险行业,建筑安全一直是行业关注的焦点。近年来,计算机视觉技术的快速发展为建筑工程安全管理提供了可能性。为全面、系统、客观地反映建筑安全领域计算机视觉技术的研究成果及其不足,运用知识图谱分析工具VOSviewer对来自WOS数据库核心合集上的166篇相关研究文献进行了可视化定量分析并辅以定性分析,分析了计算机视觉技术在建筑安全领域的研究现状与发展趋势。结果表明:计算机视觉技术在建筑安全领域应用的研究文献发表数量呈现上升趋势,并在近五年表现突出;该领域的作者研究合作群体分布分散,彼此缺乏合作;该领域的研究主题大致分为三个方向,即设备的识别与跟踪、工人不安全行为的识别以及计算机视觉及其发展;该领域未来的研究方向可能会尝试将计算机视觉技术与多种数字技术和深度学习技术相结合、增强个人防护设备检测的及时性,同时整体场景信息的获取以及综合安全监控系统设计相关技术的开发运用值得期待。  相似文献   
25.
船-桥避碰监测预警系统研究   总被引:3,自引:1,他引:2  
为提高桥区船舶航行安全,提出一种基于智能视频处理技术的船-桥避碰监测预警系统。该系统实时采集桥区场景视频,利用视频处理技术自动检测运动船舶目标,基于视觉几何模型进行船舶空间定位,提取船舶运动态势参数,并结合船舶航行操纵知识和相关模型,进行船-桥碰撞风险预测,输出避碰操纵命令。大量仿真及现场试验结果表明,该系统能检测出航行异常船舶并输出避碰操纵命令,达到主动避碰的目的。  相似文献   
26.
Guards on machine tools are meant to protect operators from injuries caused by tools, workpieces, and fragments hurled out of the machine’s working zone. This article presents the impact resistance requirements, which guards according to European safety standards for machine tools must satisfy. Based upon these standards the impact resistance of different guard materials was determined using cylindrical steel projectiles. Polycarbonate proves to be a suitable material for vision panels because of its high energy absorption capacity. The impact resistance of 8-mm thick polycarbonate is roughly equal to that of a 3-mm thick steel sheet Fe P01. The limited ageing stability, however, makes it necessary to protect poycarbonate against cooling lubricants by means of additional panes on both sides.  相似文献   
27.
一种基于视频图像相关性的火灾火焰识别方法   总被引:4,自引:1,他引:3  
由于火焰燃烧时气体羽流的卷吸特性和空气流动的影响,燃烧的火焰表现出不停的振荡特性,基于这种振荡性提出利用图像的相关性来探测火灾的发生.火灾视觉特征的提取是视觉火灾探测的重要问题,首先确定运动区域,再利用火焰振荡特性提出了相关性算法,并分析了R、G、B 3种分量对相关性的影响.实验结果表明利用相关性来分析时,火焰的相关性系数图是剧烈振荡的,而非火焰的相关性系数图是相对比较平坦的,为可视化火灾探测系统提供了一种有效的判据;R、G、B对相关性的影响是一致的,在实际应用中只需利用其中的1个分量即可,可有效提高火灾探测系统的响应时间.  相似文献   
28.
Tisza mayflies, Palingenia longicauda (Olivier 1791), swarm exclusively over the river Tisza (from which the name of the mayfly was derived). This river is bordered by a high vertical wall of trees and bushes, which hinder P. longicauda to move away horizontally from the water. During swarming, Tisza mayflies fly immediately above the river in such a way that their cerci touch the water frequently or sweep its surface. This continuous close connection with water and the vertical wall of the shore and riparian vegetation result in that Tisza mayflies never leave the water surface; consequently, they need not search for water. Several Ephemeroptera species move away far from water and return to it guided by the horizontal polarization of water-reflected light. To reveal whether also P. longicauda is or is not polarotactic, we performed a field experiment during the very short swarming period of Tisza mayflies. We show here that also P. longicauda has positive polarotaxis, which, however, can be observed only under unnatural conditions, when the animals are displaced from the water and then released above artificial test surfaces. P. longicauda is the first species in which polarotactic water detection is demonstrated albeit it never leaves the water surface, and thus, a polarotactic water detection seems unnecessary for it. The polarotactic behaviour of Tisza mayflies explains the earlier observation that these insects swarm above wet asphalt roads running next to river Tisza.  相似文献   
29.
习近平总书记在第75届联合国大会一般性辩论上发表的重要讲话为我国实现碳达峰目标和碳中和愿景指明了方向。本文针对我国如何统筹碳达峰目标与碳中和愿景工作提出如下建议:一是要充分认识我国实现碳达峰目标的困难和挑战。二是要充分认识到我国碳达峰的任务艰巨,但有一定的基础条件。三是要树立战胜困难的信心和决心。四是要认真总结北京、河北、河南、山西、四川等已经初步实现碳达峰目标地区的经验。五是统筹碳达峰与碳中和,提早安排碳中和各项工作。六是统筹提高能源效率和发展非化石能源。七是统筹能源转型和发展转型。八是成立国家碳中和发展基金。九是建立碳达峰、碳中和的政策机制。十是加强碳达峰、碳中和的国际合作。  相似文献   
30.
Ultraviolet (UV) reflectance of the plumage is common in birds and plays an important role in sexual signalling. Recently, it has been proposed that birds are able to modify plumage UV reflectance by the application of uropygial gland secretion. Based on a survey of the optical properties of this secretion from 51 species belonging to 12 avian orders, we show that two main types of uropygial secretions exist, one predominantly found in passerines and one in non-passerines, both reducing relative UV reflectance of a white background (Teflon™ tape). We quantified how each type of secretion (exemplified by blue tit and mallard) affected feather UV reflectance. Both secretions reduced overall brightness and relative UV reflectance of white mallard feathers but hardly affected the reflectance of UV/blue blue tit crown feathers. According to models of avian colour vision, changes in reflectance due to application of the secretion were at or below the discrimination threshold of most birds. We conclude that the uropygial secretion is unlikely to play a major role in modifying plumage UV reflectance. However, the optical properties of the uropygial secretion may have been selected to interfere as little as possible with visual signaling through plumage reflectance. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  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