Perhaps you should try some spelling variations:
9.13 germany » 9.16 germany, 113 germany, 2.1 germany
9.15 germany » 9.16 germany, 2.1 germany, 10.10 germany
9.14 germany » 9.16 germany, 8.4 germany, 2.1 germany
20th century » 18th century
2f history » imf history, etf history, ref history
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 %((((9.13 germany) OR (9.15 germany))) OR (9.14 germany)) %2f history %2f 20th century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22agriculture and state %((((9.13 germany) OR (9.15 germany))) or (9.14 germany)) %2f history %2f 20th century%22".
• Adding a wildcard symbol may retrieve word variants: %22agriculture and state %((((9.13 germany) OR (9.15 germany))) or (9.14 germany)) %2f history %2f 20th century%22*.