导论······························································································11
1选题背景与意义·······································································11
1选题背景········································································11
2选题意义········································································21
2研究对象概念界定····································································31
1多元化经营·····································································31
2范围经济········································································51
3文献综述················································································51
1国外研究现状··································································61
2国内研究现状··································