Perhaps you should try some spelling variations:
2f politics » 2 politics, 21 politics, 22 politics
20 politics » 2 politics, 10 politics, 21 politics
2f sources » 2 sources, 20 sources, 22 sources
21 sources » 2.1 sources, 2 sources, 1 sources

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: %((22new spain) OR (new spain)) %((2f politics) OR (20 politics)) AND government %2f 18th century %((2f sources) OR (21 sources))%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((22new spain) or (new spain)) %((2f politics) OR (20 politics)) and government %2f 18th century %((2f sources) or (21 sources))%22".
• Adding a wildcard symbol may retrieve word variants: %((22new spain) or (new spain)) %((2f politics) OR (20 politics)) and government %2f 18th century %((2f sources) or (21 sources))%22*.