Perhaps you should try some spelling variations:
"_ decolonization africa" » "_ democratization africa"
"et cooperation history" » "et corporation history", "et federation history", "et cooperations history", "eu cooperation history", "2 cooperation history"
"its colonization work" » "its colonization's mark", "its colonization songs", "its colonization _", "anti colonization work", "jews colonization work", "mars colonization work"

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