Perhaps you should try some spelling variations:
"mars communication issues" » "mars community issues", "mars communication india", "mars communication united", "mass communication issues", "mass communications issues", "markets communication issues"
"eu cooperation series" » "eu cooperation theories", "eu cooperation sources", "eu cooperation studies", "et cooperation series", "2 cooperation series", "la cooperation series"
"its migration history" » "u.s migration history", "us migration history", "cs migration history"

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: (((("mars communication issues") OR ("eu cooperation series"))) OR ("its migration history"))~.
• Removing quotes may allow a broader search: (((( mars communication issues ) or ( eu cooperation series ))) or ( its migration history ))~.
• Adding a wildcard symbol may retrieve word variants: (((("mars communication issues") or ("eu cooperation series"))) or ("its migration history"))*.