Perhaps you should try some spelling variations:
"national investment treaties series" » "international investment treaties series", "capital investment treaties series", "national treatment treaties series", "national investment strategies series", "national investment activities series", "national investment incentives series", "national investment textiles series", "national investment theories series", "national investment forestiers series"
"industrial development center series" » "industrial development case series", "industrial development century series", "industrial development gender series", "industrial development center studies"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("national investment treaties series") OR ("industrial development center series"))~.
• Removing quotes may allow a broader search: (( national investment treaties series ) or ( industrial development center series ))~.
• Adding a wildcard symbol may retrieve word variants: (("national investment treaties series") or ("industrial development center series"))*.