Perhaps you should try some spelling variations:
reef fishery » reef fishes, reef fish
20th century » 18th century
imf history » brief history
21 germany » 11 germany, 20 germany, _ germany
2 germany » _ germany, 7 germany, 2 german
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 %((21 germany) OR (2 germany)) %((reef fishery) OR (imf history)) %20 20th century%22.
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((21 germany) or (2 germany)) %((reef fishery) or (imf history)) %20 20th century%22*.