Perhaps you should try some spelling variations:
"und generative random" » "und generating random", "und generation random", "und generate random", "und degenerative random", "und generatoren random"
"sound generation radar" » "second generation radar", "based generation radar", "sound generation raman", "sound generation radio", "sound generation random"

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: (("sound generation radar") OR ("und generative random"))*.
• Removing quotes may allow a broader search: (( sound generation radar ) or ( und generative random ))*.