Perhaps you should try some spelling variations:
20 political » 10 political
22new spain » new spain
20 politics » 2 politics, 10 politics, 21 politics
22 sources » 2.2 sources, 252 sources, 12 sources
21 sources » 2.1 sources, 1 sources, 11 sources
f sources » 3 sources, 1 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: %22new spain %((20 politics) OR (20 political)) AND government %2f 18th century %((((22 sources) OR (f sources))) OR (((21 sources) OR (2 sources))))%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22new spain %((20 politics) OR (20 political)) and government %2f 18th century %((((22 sources) or (f sources))) or (((21 sources) or (2 sources))))%22".
• Adding a wildcard symbol may retrieve word variants: %22new spain %((20 politics) OR (20 political)) and government %2f 18th century %((((22 sources) or (f sources))) or (((21 sources) or (2 sources))))%22*.