Perhaps you should try some spelling variations:
"trubner methodik leitfaden" » "trubner methodischer leitfaden", "uber methodik leitfaden", "einer methodik leitfaden", "grobner methods leitfaden"
"trubner technik leitfaden" » "uber technik leitfaden", "struktur technik leitfaden"
"trigger technik leitfaden" » "trigger mechanism leitfaden"

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: (((("trubner technik leitfaden") OR ("trigger technik leitfaden"))) OR ("trubner methodik leitfaden")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"trubner technik leitfaden\") OR (\"trigger technik leitfaden\"))) or (\"trubner methodik leitfaden\"))".
• Removing quotes may allow a broader search: (((( trubner technik leitfaden ) OR ( trigger technik leitfaden ))) or ( trubner methodik leitfaden )).
• Adding a wildcard symbol may retrieve word variants: (((("trubner technik leitfaden") OR ("trigger technik leitfaden"))) or ("trubner methodik leitfaden"))*.