Perhaps you should try some spelling variations:
essener » essences
segner » segneri, stegner, segnery
diesen » dieser, diesem, dieses
beitragen » beitrag
raumforschung » frauenforschung

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: ((((essener beitrage) OR (segner beitrage))) OR (diesen beitragen)) zur raumforschung.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((essener beitrage) OR (segner beitrage))) or (diesen beitragen)) zur raumforschung".
• Adding a wildcard symbol may retrieve word variants: ((((essener beitrage) OR (segner beitrage))) or (diesen beitragen)) zur raumforschung*.