Perhaps you should try some spelling variations:
"international economy ecological studies" » "international economic ecological studies", "international economics ecological studies", "international energy ecological studies", "international economy technological studies", "international economy sociological studies", "international economy colonial studies", "international economy ecological services", "international economy archaeological studies"
"international prices economy series" » "international prices economic series", "international driven economy series", "international rich economy series", "international prices economics series"

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 prices economy series") or ("international economy ecological studies"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("international prices economy series") OR ("international economy ecological studies")).
• Removing quotes may allow a broader search: (( international prices economy series ) or ( international economy ecological studies )).
• Adding a wildcard symbol may retrieve word variants: (("international prices economy series") or ("international economy ecological studies"))*.