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   5篇
  免费   0篇
  国内免费   3篇
综合类   8篇
  2013年   1篇
  2012年   1篇
  2007年   2篇
  1958年   1篇
  1957年   1篇
  1956年   2篇
排序方式: 共有8条查询结果,搜索用时 78 毫秒
1
1.
2.
标准化对于开发“学习、教育和培训”(LET)中使用的“信息通信技术”(ICT)有重要意义,但ICT的利益相关者(stakeholders)却往往质疑标准化活动.本文提出,利用这种质疑形式来分析和改进当前的ICT标准化活动.讨论了由各方参与产生ICT标准过程的模型框架,其中一系列“为什么”的问题(Why questions)起着重要作用.讨论主要围绕两个方面:一是标准及相关事物在发展过程中的管理与核准;二是如何识别LET中的相关问题与可用来解决这些问题的创新技术.给出了两个事例: 一个是对“内容共享对象参考模型”(Sharable Content Object Reference Model, SCORM)的质疑,这能帮助理解该模型;特别是对其适用范围(scope)的质疑而使该模型更完善.另一个是对制定“新工作条款”(New Work Items)必要性的质疑,使人们认识到澄清标准中有关技术原理(rationale)的重要性.  相似文献   
3.
该报告运用文献计量学方法,对英国及其主要合作伙伴国的国际合作格局做了全面的分析。所选
择的主要国家包括美国、加拿大、法国、德国、日本、澳大利亚、中国与印度;数据覆盖领域有临床、医药
卫生、生物科学、环境科学、数学、物质科学以及工程技术领域;数据时间分为1996-2000年与2001-2005
年两个时间段。结果显示:国际论文数量增长显著;英国国际合作论文份额的增长比G7 国家更加快速; 德
国和美国是英国最大的国际合作伙伴;英国国际合作论文的平均影响力显著高于其科研论文的总体影响力;
中国与英国合作发表的论文数量超过了与其他欧洲各国的合作论文数。  相似文献   
4.
The Last Glacial Maximum (LGM, c. 26-16 ka) and the Holocene Optimum (HO, c. 9-5 ka) were characterized by cold-dry and warm-wet climates respectively in the recently geological Earth. How Chinese deserts and sand fields responded to these distinctive climatic changes is still not clear, however. To reconstruct environments of the deserts and sand fields during the LGM and HO is helpful to understand the forcing mechanisms of environment change in this arid region, and to test paleoclimatic modeling results. Through our long-term field and laboratory investigations, 400 optically stimulated luminescence (OSL) ages and more than 100 depositional records in the Chinese deserts and sand fields were obtained; on the basis of these data, we reconstruct spatial distributions of the deserts and sand fields during the LGM and HO. Our results show that the sand fields of Mu Us, Hunshandake, Horqin and Hulun Buir in northern and northeastern China had expanded 25%, 37%, 38% and 270%, respectively, during the LGM; the sand fields of Gonghe in the northeastern Qinghai-Tibetan Plateau had expanded 20%, and the deserts of Badain Jaran, Tengger in central northern China had expanded 39% and 29% separately during the LGM; the deserts of Taklimakan, Gurbantünggüt and Kumtag in northwestern China had expanded 10%-20% respectively, compared to their modern areas. On the other hand, all of the sand fields were nearly completely covered by vegetation during the HO; the deserts in northwestern and central northern China were reduced by around 5%-20% in area during this time. Lakes in this arid region were probably expanded during the HO but this conclusion needs more investigation. Compared with the geological distributions of deserts and sand fields, human activity has clearly changed (expanded) the area of active sand dunes at the present time. Our observations show that environmental conditions of Chinese deserts and sand fields are controlled by regional climate together with human activity.  相似文献   
5.
6.
7.
国际合作研究不仅可以利用其他国家的科研投资,而且能够产生具有轰动效应的创新型结果。由
于语言文化的相似性,英国与美国及欧洲国家有着较为广泛的联系,他们之间的合作是英国科学研究合作的
主体。随着科学研究及技术革新的发展更多地转向东方,以及中国和印度这两大科技力量的迅猛发展,英国
应该更加重视与这两个国家的合作。文章指出:应该就英国及其新伙伴之间的关系进行详细的研究,从而深
入理解中英两国间的合作并建立成功的合作模式。  相似文献   
8.
1
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