Perhaps you should try some spelling variations:
"international mexican economy series" » "international american economy series", "international medical economy series", "international media economy series", "international african economy series", "international american economic series", "international mexican economics series"
"international energy economic theories" » "international energy economic theory", "international energy economics series", "international energy economics theories", "international energy economy theories", "international ecology 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 energy economic theories") or ("international mexican economy series"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("international energy economic theories") OR ("international mexican economy series"))*.
• Removing quotes may allow a broader search: (( international energy economic theories ) or ( international mexican economy series ))*.