Perhaps you should try some spelling variations:
"_ decolonization africa" » "_ democratization africa"
"its colonization failed" » "its colonization still", "its organizations failed", "anti colonization failed", "jews colonization failed", "mars colonization failed"
"china cooperation history" » "china corporation history", "china federation history", "asian cooperation history", "regional cooperation 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 ("its colonization failed"))) OR ("china cooperation history"))~.
• Removing quotes may allow a broader search: (((( _ decolonization africa ) or ( its colonization failed ))) or ( china cooperation history ))~.
• Adding a wildcard symbol may retrieve word variants: (((("_ decolonization africa") or ("its colonization failed"))) or ("china cooperation history"))*.