Perhaps you should try some spelling variations:
"groups generating radar" » "groups generation radar", "groups generated radar", "groups operating radar", "groups penetrating radar", "groups penetrating radars", "groups generating random"
"groups generators radar" » "group generators radar", "groups generated radar", "groups generation radar", "groups generators random", "groups generators rated", "groups generators aat"

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