Perhaps you should try some spelling variations:
"_ decolonization africa" » "_ democratization africa"
"re colonization failed" » "re colonization still", "re organizations failed", "pro colonization failed", "_ colonization failed", "jews colonization failed"
"les federations history" » "les federation history", "les relations history", "les migrations history", "_ federations history", "les interactions 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: (((("_ decolonization africa") OR ("re colonization failed"))) OR ("les federations history"))~.
• Removing quotes may allow a broader search: (((( _ decolonization africa ) or ( re colonization failed ))) or ( les federations history ))~.
• Adding a wildcard symbol may retrieve word variants: (((("_ decolonization africa") or ("re colonization failed"))) or ("les federations history"))*.