Perhaps you should try some spelling variations:
"psychologische intelligenzforschung" » "psychologische grundlagenforschung"
"psychologische familienforschung" » "psychologischen friedensforschung", "psychologische grundlagenforschung", "psychologischer emotionsforschung"

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

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