Perhaps you should try some spelling variations:
"german colonial empire" » "german colonialism empire", "germany colonies empire", "american colonial empire"
"german colonial empires" » "german colonialism empires", "germany colonies empires", "american colonial empires"

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: (("german colonial empire") OR ("german colonial empires")).
• Removing quotes may allow a broader search: (( german colonial empire ) or ( german colonial empires )).
• Adding a wildcard symbol may retrieve word variants: (("german colonial empire") or ("german colonial empires"))*.