Perhaps you should try some spelling variations:
european conceptual » europe conceptual, european concepts, european concept
some concepts » core concepts
history self » history siege, history so, history some
history sena » history send, history sense, history set
history sea » history set, history sex, history sara
history sec » history set, history sex, history seen

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: ((european conceptual) OR (some concepts)) ((((((history sea) OR (history self))) OR (history sec))) OR (history sena))..
• The words AND, OR and NOT may confuse the search; try adding quotes: "((european conceptual) or (some concepts)) ((((((history sea) OR (history self))) or (history sec))) or (history sena)).".
• Adding a wildcard symbol may retrieve word variants: ((european conceptual) or (some concepts)) ((((((history sea) OR (history self))) or (history sec))) or (history sena)).*.