Perhaps you should try some spelling variations:
"leitfaden zur elektrotechnik" » "leitfaden der elektrotechnik", "leitfaden fur elektrotechniker", "leitfaden die elektrotechnik"
"leitfaden fur elektrotechnik" » "leitfaden fur elektrotechniker", "leitfaden der elektrotechnik", "leitfaden u elektrotechnik"

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: (("leitfaden zur elektrotechnik") OR ("leitfaden fur elektrotechnik")).
• Removing quotes may allow a broader search: (( leitfaden zur elektrotechnik ) or ( leitfaden fur elektrotechnik )).
• Adding a wildcard symbol may retrieve word variants: (("leitfaden zur elektrotechnik") or ("leitfaden fur elektrotechnik"))*.