Perhaps you should try some spelling variations:
"methode a bayes / gtt" » "methode 2 bayes / gtt", "methode als bayes / gtt", "methode _ bayes / gtt", "methode 4 bayes / gtt"
"methode 1 bayes / gtt" » "methode 2 bayes / gtt", "methode 4 bayes / gtt", "methode 5 bayes / gtt", "methode 13 bayes / gtt", "methode _ bayes / gtt"
"methode 3 bayes / gtt" » "methode 2 bayes / gtt", "methode _ bayes / gtt", "methode 4 bayes / 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 a bayes / gtt") OR ("methode 1 bayes / gtt"))) OR ("methode 3 bayes / gtt")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"methode a bayes / gtt\") OR (\"methode 1 bayes / gtt\"))) or (\"methode 3 bayes / gtt\"))".
• Removing quotes may allow a broader search: (((( methode a bayes / gtt ) OR ( methode 1 bayes / gtt ))) or ( methode 3 bayes / gtt )).
• Adding a wildcard symbol may retrieve word variants: (((("methode a bayes / gtt") OR ("methode 1 bayes / gtt"))) or ("methode 3 bayes / gtt"))*.