摘要：城市体系的空间结构具有分形特征,分维是反映空间结构优化与否的重要参量。基于分形理论,通过计算关中-天水经济区城市体系的集聚维数和关联维数,探讨分析了该经济区城市体系空间结构的特征,得出关中-天水经济区存在着核心城市不强、城市空间分布集聚不明显、城市体系等级缺失、城市之间关联较弱等制约经济区健康快速发展的因素。最后指出应进一步优化关中-天水经济区城市空间结构以便为促进经济区发展以及西咸国际大都市建设发挥持续性的积极作用。

摘要：The research studied opportunities and potential threats confronted by agricultural sustainable development, laying foundation for optimization of agricultural structure, transformation of agricultural development mode, and accomplishment of agricultural modernization. On basis of development target, development theory and route of the 13^th Five-year Plan, the research analysis the opportunities and potential threats of Yunnan agriculture and proposed policy suggestions on sustainable development of agriculture from the perspectives of ecological and competitive advantage, as well as sustainable development division in order to provide references for scientific formulation and decision-making of relevant regional planning.