Perhaps you should try some spelling variations:
"_ decolonization failed" » "_ colonization failed", "_ decolonization case", "_ decolonization africa", "decolonization _ failed"
"its cooperation sources" » "its cooperation series", "its cooperation studies", "its cooperation countries", "city cooperation sources", "et cooperation sources", "its corporation sources"
"pro colonization's mark" » "pro colonization work", "bio colonization mark", "re colonization mark"

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 sources") OR ("pro colonization's mark"))) OR ("_ decolonization failed"))~.
• Removing quotes may allow a broader search: (((( its cooperation sources ) or ( pro colonization's mark ))) or ( _ decolonization failed ))~.
• Adding a wildcard symbol may retrieve word variants: (((("its cooperation sources") or ("pro colonization's mark"))) or ("_ decolonization failed"))*.