Perhaps you should try some spelling variations:
administration reforms » administration reform, administrative reforms, administrative reform
administration regime » administration review, administrative region, administration reform
mines imperial » kings imperial, sizes imperial, chinese imperial
iron » ion

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: iron mines imperial ((administration regime) OR (administration reforms)) of china.
• Adding a wildcard symbol may retrieve word variants: iron mines imperial ((administration regime) or (administration reforms)) of china*.