Perhaps you should try some spelling variations:
2f politics » 2 politics, 21 politics, 22 politics
20 politics » 2 politics, 10 politics, 20 political
2.1 sources » 2.2 sources, 5.2 sources, 3.2 sources
2f sources » 20 sources, 22 sources, 23 sources
21 sources » 21 source, 21 resources, 2.2 sources
11 sources » 13 sources, 3 sources, 4 sources

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: %new spain %((2f politics) OR (20 politics)) AND government %2f 18th century %((2f sources) OR (((((((21 sources) OR (11 sources))) OR (2.1 sources))) OR (2 sources))))%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%new spain %((2f politics) or (20 politics)) and government %2f 18th century %((2f sources) or (((((((21 sources) OR (11 sources))) or (2.1 sources))) or (2 sources))))%22".
• Adding a wildcard symbol may retrieve word variants: %new spain %((2f politics) or (20 politics)) and government %2f 18th century %((2f sources) or (((((((21 sources) OR (11 sources))) or (2.1 sources))) or (2 sources))))%22*.