Perhaps you should try some spelling variations:
international history » transnational history, international regulatory
national historic » national historical, national histories, nations history
national history » natural history, transnational history, personal history

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: "((national historic) OR (((national history) OR (international history)))) sites of canada.
• The words AND, OR and NOT may confuse the search; try adding quotes: "\"((national historic) or (((national history) OR (international history)))) sites of canada".
• Removing quotes may allow a broader search: ((national historic) or (((national history) OR (international history)))) sites of canada.
• Adding a wildcard symbol may retrieve word variants: "((national historic) or (((national history) OR (international history)))) sites of canada*.