Perhaps you should try some spelling variations:
military part » military art, military a, military acts
19th century » 18th century
20th century » 18th century
ref history » reef history, brief history, bief history

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: %military part AND science %ref history %2f ((19th century) OR (20th century))%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%military part and science %ref history %2f ((19th century) OR (20th century))%22".
• Adding a wildcard symbol may retrieve word variants: %military part and science %ref history %2f ((19th century) OR (20th century))%22*.