Perhaps you should try some spelling variations:
military acts » military art, military actions, military aspects
etf history » reef history, imf history, ref history
2f history » imf history, ref history, tnf history
2012 19th » 2012 12th, 2019 19th, 2012 9th
2.1 19th » 2019 19th, 2018 19th, 2016 19th

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: %military acts AND science %((2f history) OR (etf history)) %((2.1 19th) OR (2012 19th)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%military acts and science %((2f history) OR (etf history)) %((2.1 19th) or (2012 19th)) century%22".
• Adding a wildcard symbol may retrieve word variants: %military acts and science %((2f history) OR (etf history)) %((2.1 19th) or (2012 19th)) century%22*.