Perhaps you should try some spelling variations:
2f germany » 2 germany, 20 germany, 25 germany
21 germany » 2.1 germany, 11 germany, 2 germany
2f history » 2.1 history, imf history, etf history
1990 20th » 1995 20th, 1999 20th, 1990 2000
1994 20th » 1995 20th, 1999 20th, 1994 10th
90 20th » 20 20th, 94 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 (21 germany)) %2f history %((((90 20th) OR (1990 20th))) OR (1994 20th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((2f germany) OR (21 germany)) %2f history %((((90 20th) or (1990 20th))) or (1994 20th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((2f germany) OR (21 germany)) %2f history %((((90 20th) or (1990 20th))) or (1994 20th)) century%22*.