Perhaps you should try some spelling variations:
american colonization » americans colonization
colonization empire » colonization pre, colonization exile, consolidation empire
colonies empire » colonial empire, colonial empires, colonialism empire

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: "((\"american colonization empire\") or (\"american ((colonies empire) OR (coloured empire))\"))".
• Removing quotes may allow a broader search: (( american colonization empire ) or ( american ((colonies empire) or (coloured empire)) )).