Perhaps you should try some spelling variations:
16th century » 18th century, 20th century
19th century » 18th century, 20th century
17th century » 18th century, 20th century
religious » religion
christianity » christian

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: economics religious aspects christianity history ((((16th century) OR (19th century))) OR (17th century)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "economics religious aspects christianity history ((((16th century) OR (19th century))) or (17th century))".
• Adding a wildcard symbol may retrieve word variants: economics religious aspects christianity history ((((16th century) OR (19th century))) or (17th century))*.