多中心城市区域空间协调发展研究：以长三角为例：take Yangtse River Delta as example 经济发展、城乡统筹、居民生活质量与生态效率耦合协调发展研究：以长三角地区为例：taking the Yangtze river delta as an example take Yangtse River Delta as example 区域创新系统中的协同效应理论与实证研究：以长三角为例：take the Yangtze River Delta region as an example reduction mechanism in the yangtze river delta as an example