Perhaps you should try some spelling variations:
"its cooperation studies" » "its cooperation series", "its cooperation sources", "its cooperation implies", "et cooperation studies", "its corporation studies", "its operation studies"
"city cooperation history" » "city corporation history", "city federation history", "china cooperation history", "city corporations history"
"jews colonization _" » "its colonization _", "mars colonization _", "re colonization _"

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: (((("its cooperation studies") OR ("jews colonization _"))) OR ("city cooperation history"))~.
• Removing quotes may allow a broader search: (((( its cooperation studies ) or ( jews colonization _ ))) or ( city cooperation history ))~.
• Adding a wildcard symbol may retrieve word variants: (((("its cooperation studies") or ("jews colonization _"))) or ("city cooperation history"))*.