Perhaps you should try some spelling variations:
"aei studies on series trends negotiations." » "aei studies on series trade negotiations.", "aei studies on series treaty negotiations.", "aei studies on series trade negotiation.", "asian studies on series trends negotiations.", "case studies on series trends negotiations."
"aei studies on services trade regulation." » "asian studies on services trade regulation.", "case studies on services trade regulation."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("aei studies on series trends negotiations.") or ("aei studies on services trade regulation."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("aei studies on series trends negotiations.") OR ("aei studies on services trade regulation."))*.
• Removing quotes may allow a broader search: (( aei studies on series trends negotiations. ) or ( aei studies on services trade regulation. ))*.