Perhaps you should try some spelling variations:
trubner methodischer » uber methodische, erster methodischer, neuer methodischer
trubner methodik » uber methodik, einer methodik, grobner methods
trubner technik » uber technik, trigger technik, struktur technik

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