Perhaps you should try some spelling variations:
tnf history » imf history, ref history, motif history
etf history » reef history, imf history, ref history
21 germany » 2.1 germany, 11 germany, 20 germany
2 germany » 12 germany, 7 germany, 2 german
1990 20th » 1995 20th, 1999 20th, 1994 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 %((21 germany) OR (2 germany)) %((tnf history) OR (etf history)) %((20 20th) OR (1990 20th)) century%22.
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((21 germany) or (2 germany)) %((tnf history) or (etf history)) %((20 20th) or (1990 20th)) century%22*.