Perhaps you should try some spelling variations:
"mass communication theory" » "mass communication technology", "maps communication theory"
"africa colonization still" » "arrival colonization still", "africa cooperation still", "africa organization still", "africa colonization failed", "africa colonization israel"
"its colonization songs" » "its colonization work", "its decolonization notes", "anti colonization songs", "jews colonization songs", "mars colonization songs"

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: (((("africa colonization still") OR ("its colonization songs"))) OR ("mass communication theory"))~.
• Removing quotes may allow a broader search: (((( africa colonization still ) or ( its colonization songs ))) or ( mass communication theory ))~.
• Adding a wildcard symbol may retrieve word variants: (((("africa colonization still") or ("its colonization songs"))) or ("mass communication theory"))*.