Perhaps you should try some spelling variations:
"methode vii bavel / gtt" » "methoden vii bavel / gtt", "methods vii bavel / gtt", "method vii bavel / gtt", "methode van bavel / gtt", "methode vii bases / gtt"
"methode von bavel / gtt" » "methode van bavel / gtt", "methode von babel / gtt", "methode von gavel / gtt"
"methode von havel / gtt" » "methode von gavel / gtt", "methode von hagel / gtt", "methode von hagen / gtt"

Try widening your search to All Fields.

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: (("methode vii bavel / gtt") OR ((("methode von bavel / gtt") OR ("methode von havel / gtt")))).
• Removing quotes may allow a broader search: (( methode vii bavel / gtt ) or ((( methode von bavel / gtt ) or ( methode von havel / gtt )))).
• Adding a wildcard symbol may retrieve word variants: (("methode vii bavel / gtt") or ((("methode von bavel / gtt") or ("methode von havel / gtt"))))*.