求翻译：“十五”以来，中国农业科学院联合全国各省（市、自治区）农业科学院和农业大学，发起成立了全国农业科研协作网，并进一步提出了建设以国家农业科技创新中心、区域农业科技创新中心和农业科技试验站为核心内涵的国家农业科技创新体系的战略构想。是什么意思？

"15", the Chinese Academy of Agricultural Sciences provinces (municipalities and autonomous regions), the Academy of Agricultural Sciences and Agricultural University, initiated the establishment of a collaborative network of national agricultural research, and further proposed the construction of t

Since the " 15" Chinese Academy of Agriculture The the provinces (municipalities throughout the country, and Agricultural Academy of Sciences and autonomous regions), initiated the establishment of an agricultural college, the national agricultural research and development collaboration site, and fu