Perhaps you should try some spelling variations:
immigration countries » immigration policies
nature conservation » resource conservation
toward immigration » toward migration, towards integration
supply toward » support toward
supply nature » supply figure

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

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