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   9篇
  免费   4篇
  国内免费   1篇
测绘学   1篇
大气科学   1篇
地球物理   3篇
地质学   1篇
综合类   4篇
自然地理   4篇
  2022年   2篇
  2014年   2篇
  2013年   2篇
  2011年   1篇
  2009年   1篇
  2008年   2篇
  2004年   1篇
  2003年   2篇
  2001年   1篇
排序方式: 共有14条查询结果,搜索用时 15 毫秒
11.
卤水资源开发利用技术述评   总被引:18,自引:11,他引:18       下载免费PDF全文
总结并论述了国内外从卤水中提取钾、镁、锂、硼、溴等资源的分离提取技术 ,并对其技术的应用范围、优缺点及技术发展趋势进行了述评  相似文献   
12.
随着导航定位技术和信息技术的发展,消费者对导航地图有了新的、更高的要求.市场上导航地图产品众多,同质化严重,如果做不到技术创新,很难继续生存下去.为了探究导航地图未来发展趋势和前景,本文针对导航地图的发展现状进行详细分析,从时间、技术层面将导航地图分为导航地图1.0和导航地图2.0.导航地图1.0主要表现形式有:二维电子地图、2.5维地图、遥感影像,导航地图2.0应包括二维矢量地图、高精度导航数据、三维地图、室内地图,支持语音导航、网络云导航.经过详细对比分析发现,导航地图1.0技术已经非常成熟,导航地图2.0虽然已经出现,但是还有很多技术、数据、硬件问题,停留在1.0到2.0的过渡阶段,称之为1.5.而导航地图产品未来能否成功,关键是能否成功过渡到2.0,在这一过程中,部分盈利模式单一,技术积累薄弱的公司将被淘汰.人们对地图认知的不断提高,希望导航地图能够更直观、更精细、更准确、更便捷、更快,新的导航地图能否成功应用,除了依赖于地图技术本身的发展,也依赖导航定位技术和IT产业发展.  相似文献   
13.
Measuring Spatial Differences of Informatization in China   总被引:1,自引:1,他引:0  
As the wide application of new Information and Communication Technologies (ICTs) shows, the world is moving fast to- wards an information age. Since China was first connected to the Internet in 1994, the development of ICTs in China and around the world has been astonishingly fast, and yet there is a clear 'digital divide' among different regions in China. Although Chinese geogra- phers have paid attention to regional differences in informatization, they usually employ a limited number of indicators, mainly focusing on the Intemet. In fact, infi~rmatization is a much broader concept, covering not only the lntemet, but also mobile phones as well as user ability. In the light of these considerations, this study provides a comprehensive examination of the development of informatization and its spatial differences in China. First, based on a literature review, the paper identifies 29 preliminary indicators for measuring informa- tization, and employs prin,-ipal components analysis and the fuzzy analytic hierarchy process to streamline them into 12 indicators to form an ICTs Developmen: Index (ID1). Second, by using the data from provincial statistical yearbooks and the China Internet Network Information Center, the paper calculates the 1191 of each mega-region and each province in 2000-2010, and measures the changing spa- tial differences in the development of informatization in China. Lastly, the paper quantifies the relationship between informatization and economic growth. The empirical results show that the IDI of the western and central China has been increasing faster than that of the coastal region, indicating that the digital divide in China has been narrowing.  相似文献   
14.
Long-term global emission scenarios enable the analysis of future climate change, impacts, and response strategies by providing insight into possible future developments and linking these different climate research elements. Such scenarios play a crucial role in the climate change literature informing the Intergovernmental Panel on Climate Change’s (IPCC) Assessment Reports (ARs) and support policymakers. This article reviews the evolution of emission scenarios, since 1990, by focusing on scenario critiques and responses as published in the literature. We focus on the issues raised in the critiques and the possible impact on scenario development. The critique (280) focuses on four areas: 1) key scenario assumptions (40%), 2) the emissions range covered by the scenarios and missing scenarios (25%), 3) methodological issues (24%), and 4) the policy relevance and handling of uncertainty (11%). Scenario critiques have become increasingly influential since 2000. Some areas of critique have decreased or become less prominent (probability, development process, convergence assumptions, and economic metrics). Other areas have become more dominant over time (e.g., policy relevance & implications of scenarios, transparency, Negative Emissions Technologies (NETs) assumptions, missing scenarios). Several changes have been made in developing scenarios and their content that respond to the critique.  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