Perhaps you should try some spelling variations:
2017 germany » 20 germany, 17 germany, 2006 germany
21 germany » 11 germany, 2 germany, 20 germany
2f history » etf history, ref history, tnf history
20 18th » 2017 18th, 2021 18th, 2018 18th

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: %22agriculture AND state %((21 germany) OR (2017 germany)) %((2f history) OR (((imf history) OR (brief history)))) %20 18th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((21 germany) or (2017 germany)) %((2f history) or (((imf history) OR (brief history)))) %20 18th century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((21 germany) or (2017 germany)) %((2f history) or (((imf history) OR (brief history)))) %20 18th century%22*.