Perhaps you should try some spelling variations:
20th century » 18th century
reef history » brief history, reeves history, reef fishery
tnf history » ref history, motif history, stone history
etf history » ref history, beruf history, ethis history
imf history » brief history
21 germany » 2 germany, 20 germany, 7 germany
11 germany » 11 german, 1918 germany, 7 germany
2f germany » 2 germany, 20 germany, 25 germany
2 german » 3 german, 5 german
2f 20th » 20 20th, 2.2 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 (2 german))) OR (((21 germany) OR (11 germany)))) %((((reef history) OR (((etf history) OR (tnf history))))) OR (imf history)) %2f 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((((2f germany) or (2 german))) or (((21 germany) OR (11 germany)))) %((((reef history) or (((etf history) or (tnf history))))) or (imf history)) %2f 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((((2f germany) or (2 german))) or (((21 germany) OR (11 germany)))) %((((reef history) or (((etf history) or (tnf history))))) or (imf history)) %2f 20th century%22*.