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