Perhaps you should try some spelling variations:
"national property economic status" » "national poverty economic status", "functional property economic status", "national project economic status", "national property economic sectors", "national property socioeconomic status"
"international prices economic theories" » "international prices economic theory", "international prices economics series", "international crises economic theories", "international prices econometric theories", "international services economic theories"

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

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