Perhaps you should try some spelling variations:
"psychologists" » "psychological", "psychologie"
"psychologies" » "psychologie", "psychologist", "psychologin"
"psychologe" » "psychologie", "psychology", "psychologique"
"psychologen" » "psychologien", "psychologyn", "psychologiquen", "psychology", "psychologie"

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: ("psychologists" OR (("psychologies" OR "psychologe") OR "psychologen")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(\"psychologists\" or ((\"psychologies\" OR \"psychologe\") or \"psychologen\"))".
• Removing quotes may allow a broader search: ( psychologists or (( psychologies OR psychologe ) or psychologen )).
• Adding a wildcard symbol may retrieve word variants: ("psychologists" or (("psychologies" OR "psychologe") or "psychologen"))*.