Perhaps you should try some spelling variations:
2017 germany » 20 germany, 17 germany, 2006 germany
2.1 germany » 9.13 germany, 9.14 germany, 9.15 germany
2f germany » 2 germany, 20 germany, 25 germany
21 germany » 11 germany, 2 germany, 20 germany
2f 20th » 2.2 20th
20 20th » 90 20th, 2019 20th, 2020 20th

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 %((2f germany) OR (((((2.1 germany) OR (21 germany))) OR (2017 germany)))) %brief history %((2f 20th) OR (20 20th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((2f germany) or (((((2.1 germany) OR (21 germany))) or (2017 germany)))) %brief history %((2f 20th) or (20 20th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((2f germany) or (((((2.1 germany) OR (21 germany))) or (2017 germany)))) %brief history %((2f 20th) or (20 20th)) century%22*.