共查询到20条相似文献,搜索用时 46 毫秒
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俄罗斯和澳大利亚农业比较研究 总被引:1,自引:0,他引:1
俄罗斯和澳大利亚的自然禀赋相近,然而两国农业发展水平差距巨大。澳大利亚是高效农业,商品化、国际化程度高,有3/4的“富余”产品出口国外;俄罗斯则自给不足,肉、奶、蛋、土豆等依赖进口。本文从土地所有权、农业生产主体和农业生产分工三个角度出发,分析造成俄、澳农业劳动生产率差距的原因,探讨提高土地利用率、规模与效率以及市场对组织生产的调节作用等问题。 相似文献
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本文对澳大利亚维多利亚州肭屏(Nepean)半岛海岸悬崖风成岩古土壤序列沉积学地层的成土母质来源、成土时期的环境、时代等问题进行研究。 相似文献
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宁夏西吉地区滑坡灾害地貌的成因分析 总被引:7,自引:0,他引:7
宁夏西吉地区滑坡灾害地貌是海原地震区最严重的地形变特征。本文在分析区域滑坡呈 或团块状密集独特分布及其严重灾害特征的基础上,进一步探讨了它的成因机制。表明滑坡地形奕的分布规律不仅受地震烈度的影响,而且还受诸如黄土的自然特征,地质构造,地貌结构和区域新构造运行等自然环境的控制. 相似文献
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Edward A. Bryant Robert W. Young David M. Price David J. Wheeler Mark I. Pease 《自然地理学》2013,34(5):440-459
The Jervis Bay area offers a diversity of landforms that do not fit within contemporary views of coastal evolution. Field evidence indicates that catastrophic tsunami have had a significant impact on the coast and its hinterland both within and outside the embayment. Runup has overtopped cliffs 80 m above sea level and deposited chevron-shaped ridges to elevations of 130 m on the southern headland. Boulders, up to 6 m in diameter, have been deposited in an imbricated fashion against cliffs, on clifftops, and along shoreline ramps. Bed-form features and the size of transported material indicate flow depths up to 10 m and velocities around 8 m s-1. While significant Pleistocene material has been swept onto the coastline, mainly in the form of barriers, radiocarbon dating indicates that tsunami have occurred repetitively throughout the Holocene. The most recent event occurred just before European settlement over 200 years ago. [Key words: barrier beaches, coastal geomorphology, tsunami, Jervis Bay, Australia.] 相似文献
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