Perhaps you should try some spelling variations:
naturalistic approach » pluralistic approach, heuristic approach, humanistic approach
futuristic approach » heuristic approach, humanistic approach, metaheuristic approach
realistic approach » realist approach, holistic approach, heuristic approach

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: ((((naturalistic approach) OR (realistic approach))) OR (futuristic approach)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((naturalistic approach) OR (realistic approach))) or (futuristic approach))".
• Adding a wildcard symbol may retrieve word variants: ((((naturalistic approach) OR (realistic approach))) or (futuristic approach))*.