Perhaps you should try some spelling variations:
"international poverty economic series" » "national poverty economic series", "international property economic series", "international forestry economic series", "international energy economic series", "international poverty economics series", "international poverty economic services", "international poverty economy series"
"national policy economic theories" » "national policy economic theory", "national policy economics series", "national poverty 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 poverty economic series") or ("national policy economic theories"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("international poverty economic series") OR ("national policy economic theories")).
• Removing quotes may allow a broader search: (( international poverty economic series ) or ( national policy economic theories )).
• Adding a wildcard symbol may retrieve word variants: (("international poverty economic series") or ("national policy economic theories"))*.