Perhaps you should try some spelling variations:
ref history » reef history, brief history, bief history
imf history » brief history
11 germany » 11 german, 1918 germany, 7 germany
2023 20th » 2023 26th, 2023 10th, 2020 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 %11 germany %((ref history) OR (imf history)) %((((20 20th) OR (2023 20th))) OR (20((20 20th) OR (2023 20th)))) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %11 germany %((ref history) or (imf history)) %((((20 20th) OR (2023 20th))) or (20((20 20th) OR (2023 20th)))) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %11 germany %((ref history) or (imf history)) %((((20 20th) OR (2023 20th))) or (20((20 20th) OR (2023 20th)))) century%22*.