全文获取类型
收费全文 | 131篇 |
免费 | 3篇 |
出版年
2023年 | 1篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 10篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 49篇 |
2012年 | 9篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1981年 | 2篇 |
1979年 | 2篇 |
排序方式: 共有134条查询结果,搜索用时 78 毫秒
32.
33.
34.
35.
36.
Human-induced changes to global climate have become increasingly difficult to ignore in recent years. As the frequency and severity of extreme weather events increases, the impacts on both natural and human systems are becoming difficult to manage with the current policies. In Canada, one of the most vulnerable regions to climate change is the Arctic, where temperatures are rising at a rate two to three times that of the global average. Warmer seasonal temperatures have led to melting permafrost and increased variability in sea ice conditions, which has contributed to a rise in coastal erosion. The ongoing resilience of Arctic communities will depend heavily on their ability to implement successful long-term adaptation policies. The development and implementation of any action on climate change adaptation should involve collaboration with local stakeholders in order to reflect the views and experience of those living in the Arctic. 相似文献
37.
38.
39.
40.
This paper provides the first systematic assessment of blanket mire degradation in the east Cheviot Hills, Northumberland. The extent of erosion is mapped over a 32 km2 area of peat. Erosion affects 37% of the blanket peat. Erosion forms consist of anastomosing (7%), linear (21%) and dendritic (9%) gully systems together with peat slides (<1%). Topography is the primary influence on gully system pattern. Spatial variations in gully form can be partly explained by position in the stream network (stream order) and local variations in the depth of peat. A sequential scheme of gully development is described. Gullies evolve initially through a phase of rapid downcutting to the peat base, followed by lateral erosion and gully widening becoming dominant through a process of roughly parallel wall retreat. As gully width increases re‐deposition of peat occurs and re‐vegetation occurs on the gully floor. Comparative photography reveals that gully patterns have been stable over the past 32 years and in some areas for over 70 years. It is possible that gully systems in places are in excess of 500 years old. 相似文献