Perhaps you should try some spelling variations:
21 germany » 11 germany, 20 germany, _ germany
2f history » imf history, etf history, ref history
2 germany » _ germany, 7 germany, 2 german
2017 18th » 2017 16th, 2017 4th, 2017 5th
2017 14th » 2018 14th, 2017 4th

Try widening your search to All Fields.

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 (2 germany)) %2f history %((2017 18th) OR (2017 14th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((21 germany) or (2 germany)) %2f history %((2017 18th) OR (2017 14th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((21 germany) or (2 germany)) %2f history %((2017 18th) OR (2017 14th)) century%22*.