Perhaps you should try some spelling variations:
"methode van bavel / gtt" » "methode von bavel / gtt", "methode vi bavel / gtt", "methode vii bavel / gtt", "methode vian bavel / gtt", "methode 2an bavel / gtt", "methode 4an bavel / gtt"
"methode v bavel / gtt" » "methode vi bavel / gtt", "methode 2 bavel / gtt", "methode 4 bavel / gtt", "methode v bavula / gtt"
"methode 3 bavel / gtt" » "methode 2 bavel / gtt"
"methode 3 basel / gtt" » "methode 2 basel / gtt", "methode 3 base / gtt", "methode 3 based / gtt", "methode 3 bases / 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 van bavel / gtt") OR ((("methode v bavel / gtt") OR ((("methode 3 bavel / gtt") OR ("methode 3 basel / gtt")))))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"methode van bavel / gtt\") or (((\"methode v bavel / gtt\") or (((\"methode 3 bavel / gtt\") OR (\"methode 3 basel / gtt\"))))))".
• Removing quotes may allow a broader search: (( methode van bavel / gtt ) or ((( methode v bavel / gtt ) or ((( methode 3 bavel / gtt ) OR ( methode 3 basel / gtt )))))).
• Adding a wildcard symbol may retrieve word variants: (("methode van bavel / gtt") or ((("methode v bavel / gtt") or ((("methode 3 bavel / gtt") OR ("methode 3 basel / gtt"))))))*.