Perhaps you should try some spelling variations:
"international political ecological services" » "international policy ecological services", "international political economic services", "international political economics services", "international social ecological services", "international political hydrological services", "international political clinical services", "international political meteorological services"
"international energy economic services" » "international best economic services", "international energy economic surveys", "international energy economic studies", "international energy economic survey", "international energy economics services", "international energy economy services"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("international political ecological services") or ("international energy economic services"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("international political ecological services") OR ("international energy economic services")).
• Removing quotes may allow a broader search: (( international political ecological services ) or ( international energy economic services )).
• Adding a wildcard symbol may retrieve word variants: (("international political ecological services") or ("international energy economic services"))*.