Perhaps you should try some spelling variations:
"mars colonization failed" » "mars colonization still", "mars organizations failed", "mrsa colonization failed", "its colonization failed", "jews colonization failed"
"city cooperation studies" » "city cooperation series", "city cooperation sources", "city cooperation implies", "city corporation studies", "china cooperation studies", "city corporations studies"
"et cooperation history" » "et corporation history", "et federation history", "et cooperations history", "eu cooperation history", "2 cooperation history"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("mars colonization failed") or ("city cooperation studies"))) or ("et cooperation history"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("mars colonization failed") OR ("city cooperation studies"))) OR ("et cooperation history"))*.
• Removing quotes may allow a broader search: (((( mars colonization failed ) or ( city cooperation studies ))) or ( et cooperation history ))*.