全文获取类型
收费全文 | 71篇 |
免费 | 1篇 |
专业分类
安全科学 | 3篇 |
废物处理 | 1篇 |
环保管理 | 14篇 |
综合类 | 13篇 |
基础理论 | 22篇 |
污染及防治 | 9篇 |
评价与监测 | 2篇 |
社会与环境 | 7篇 |
灾害及防治 | 1篇 |
出版年
2022年 | 1篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 6篇 |
2012年 | 5篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
排序方式: 共有72条查询结果,搜索用时 15 毫秒
71.
A graduated licensing (GL) program was introduced in Nova Scotia, Canada, in October 1994. Previous research has shown that it reduced collisions in the short term. The present study examined the relative contribution of each stage of the program (i.e., learner and intermediate levels) and the program's impact after beginning drivers graduated to full licensure. The research focused on teenage beginning drivers (age 16-17), but the effects on older beginners also was examined. Per-driver crash rates of two groups of novices selected from driver records in Nova Scotia were compared. One group (pre-GL) received their learner's permits during the 2 years before the program was implemented, and the second group (GL) received their learner's permits during the 2 years after implementation. The findings clearly establish that most of the collision reduction in Nova Scotia's program occurred during the first year of the program, particularly during the first 6 months when the majority of novices were driving under supervision. The collision rate for 16 to 17-year-old GL novices was 50% lower than the rate for pre-GL novices during the 6 months after they received their learner's permits, and about 10% lower during their first 2 years of licensure when unsupervised driving from midnight to 5 A.M. was prohibited. Much of this improvement for 16 to 17-year-olds occurred during restricted night hours. Collision rates also were lower during nonrestricted hours in the initial 6 months of licensure. The 3-month "time discount" for driver education provided no safety benefit, and GL novices with driver education had collision rates that were not lower than pre-GL novices. There was no long-term effect found for the program after 16 to 17-year-olds graduated to full licensure. For older beginning drivers, crash rates during the first year after obtaining a learner's permit showed a 31% reduction. This effect diminished rapidly. There was only a 2% reduction during the first year of licensure, and crash rates increased during the following 2 years. Overall the data indicate substantial benefits of graduated licensing for 16 to 17-year-old beginners, but no benefits beyond the learner stage for older beginners. 相似文献
72.
Katharine Farrell 《Local Environment》2013,18(5):469-479
While policy network theory employs complexity concepts (self-regulation, emergence) mainly as explanatory tools, potential theoretical contributions arising from the underpinning analytical principles have been less explored. It is argued that by directly considering multi-level environmental governance as a far-from-equilibrium complex system, it is possible to explore how governance structures might better support and construe the dynamic and delicate conditions necessary for the presence of life. Problem formulation or 'agenda setting' powers exerted by civil servants and scientists are examined as emergent properties, systemic in and necessary for the stability of multi-level governance structures. Finally, it is proposed that multi-level environmental governance design may be improved through a reconceptualisation of representation, informed by principles from complexity theory, which embraces and 'recaptures' power exerted through extra-electoral governance relationships. 相似文献