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", "trigger technik leitfaden", "struktur technik leitfaden"

You may be able to get more results by adjusting your search query.

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