Perhaps you should try some spelling variations:
immigration policies » immigration policy, migration policy
rates immigration » race immigration, sites immigration, values immigration
den international » den internationalen, when international, can international
supply rates » supply water
supply den » supply ann, supply demand, supply design
prices. » price.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( supply rates immigration policies. ) or ( supply den international prices. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( supply rates immigration policies. ) OR ( supply den international prices. )).
• Adding a wildcard symbol may retrieve word variants: (( supply rates immigration policies. ) or ( supply den international prices. ))*.