Perhaps you should try some spelling variations:
american colonial » american colonies, american colonization
colonial empire » colonial empires
colonies empire » colonial empires, colonialism empire, colonies exposed

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "\"((\\"american colonial empire\\") or (\\"american ((colonies empire) OR (coloured empire))\\"))\"".
• Removing quotes may allow a broader search: (( american colonial empire ) or ( american ((colonies empire) OR (coloured empire)) )).