Perhaps you should try some spelling variations:
"sound generation random" » "sound generating random", "sound generator random", "sound generalized random", "second generation random", "based generation random"
"sound generation radar" » "second generation radar", "based generation radar", "sound generation raman", "sound generation radio", "sound generation rotary"
"sound generated random" » "sound generalized random", "sound generating random", "sound general random", "wind generated random"

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: (((("sound generation radar") OR ("sound generation random"))) OR ("sound generated random")).
• Removing quotes may allow a broader search: (((( sound generation radar ) or ( sound generation random ))) or ( sound generated random )).
• Adding a wildcard symbol may retrieve word variants: (((("sound generation radar") or ("sound generation random"))) or ("sound generated random"))*.