Perhaps you should try some spelling variations:
"sound generating radar" » "sound generation radar", "sound generated radar", "und generative radar", "sound penetrating radar", "sound penetrating radars", "sound generating random"
"und generation radar" » "und generation raman", "und generation radio", "und generation random", "sound generation radar", "und regeneration radar", "wind generation radar"

Try widening your search to All Fields.

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