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   95篇
  免费   7篇
  2023年   1篇
  2022年   1篇
  2020年   2篇
  2019年   5篇
  2018年   5篇
  2017年   9篇
  2016年   6篇
  2015年   1篇
  2014年   2篇
  2013年   26篇
  2012年   3篇
  2011年   4篇
  2010年   6篇
  2009年   3篇
  2007年   3篇
  2006年   1篇
  2005年   1篇
  2004年   1篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  2000年   1篇
  1985年   1篇
  1983年   2篇
  1982年   2篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1975年   1篇
  1974年   1篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   2篇
排序方式: 共有102条查询结果,搜索用时 21 毫秒
1.
Policies concerning undocumented immigrants are inevitably ambivalent, creating uncertainty and confusion in the implementation process. We identify a clear example of this ambivalence —U.S. law setting standards for determining the credibility of asylum seekers—that resulted in an increase in asylum grants despite policymakers' intention to make it harder for individuals to obtain the status. We argue that this law, The REAL ID Act of 2005, sent mixed messages to immigration judges (IJs), street-level bureaucrats who implement immigration policy. It increased IJ discretion, but set vague limits. We theorize that IJs, behaving in a bounded rationality framework, use their professional legal training as a short-cut and look primarily to the courts for guidance. Our evidence supports our argument. After the passage of the REAL ID Act, IJ decision-making is more closely aligned with the preferences of their political and legal principals, and, in the final score, the federal circuit courts are the winners.  相似文献   
2.
3.
4.
5.
Invasive vegetation species can lead to major changes in the geomorphology of coastal systems. Within temperate estuaries in the southern hemisphere, especially Australia and New Zealand, the cordgrass Spartina spp. has become established. These species are highly invasive, and their prolific growth leads to the development of supratidal environments in formerly intertidal and subtidal environments. Here, we quantified the impact of Spartina invasion on the geomorphology and sequestration capacity of carbon in the sediments of Anderson Inlet, Victoria, Australia. Spartina was first introduced to the area in the 1930s to aid in land reclamation and control coastal erosion associated with coastal development. We found that Spartina now dominates the intertidal areas of the Inlet and promotes accretion (18 mm/year) causing the formation of over 108 ha of supratidal islands over the past 100 years. These newly formed islands are calculated to potentially contain over 5.5 million tonnes of CO2 equivalent carbon. Future management of the inlet and other Spartina‐dominated environments within Australian presents a dilemma for resource managers; on the one hand, Spartina is highly invasive and can outcompete native tidal marshes, thereby warranting its eradication, but on the other hand it is likely more resilient to rising sea levels and has the potential for carbon sequestration. Whether or not the potential advantages outweigh the significant habitat change that is anticipated, any management strategies will likely require additional research into costs and benefits of all ecosystem services provided by Spartina including in relation to nutrient cycling, shoreline stabilisation, and biodiversity as well as in response to the longevity of carbon found within the sediments.  相似文献   
6.
7.
8.
9.
10.
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