Perhaps you should try some spelling variations:
1918 germany » 8 germany
reef history » brief history, reeves history, reef fishery
2f germany » 2 germany, 21 germany, 25 germany
20 germany » 2 germany, _ germany, 7 germany
2020 20th » 2020 16th, 2020 5th, 2020 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 %((((2f germany) OR (20 germany))) OR (1918 germany)) %reef history %((2020 20th) OR (2020 2021)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((((2f germany) OR (20 germany))) or (1918 germany)) %reef history %((2020 20th) or (2020 2021)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((((2f germany) OR (20 germany))) or (1918 germany)) %reef history %((2020 20th) or (2020 2021)) century%22*.