Perhaps you should try some spelling variations:
"historian of philosophy" » "historia of philosophy", "histories of philosophy", "historic of philosophy"
"historians of philosophy" » "historias of philosophy", "historiess of philosophy", "historics of philosophy", "histories of philosophy"

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: (((("historian of philosophy") OR ("historians of philosophy"))) OR ("historical of philosophy")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"historian of philosophy\") OR (\"historians of philosophy\"))) or (\"historical of philosophy\"))".
• Removing quotes may allow a broader search: (((( historian of philosophy ) OR ( historians of philosophy ))) or ( historical of philosophy )).
• Adding a wildcard symbol may retrieve word variants: (((("historian of philosophy") OR ("historians of philosophy"))) or ("historical of philosophy"))*.