Perhaps you should try some spelling variations:
"linkage groups" » "linkage group"
"life groups" » "life group", "line groups", "elite groups"
"like groups" » "large groups", "crime groups"
"link groups" » "sink groups", "disk groups", "linear groups"
"lie groups" » "live groups", "line groups"

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: (((((("life groups") OR ("lie groups"))) OR ("like groups"))) OR ((((("linkage groups") OR ("link groups"))) OR ("risk groups")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((((\"life groups\") OR (\"lie groups\"))) or (\"like groups\"))) or (((((\"linkage groups\") or (\"link groups\"))) or (\"risk groups\"))))".
• Removing quotes may allow a broader search: (((((( life groups ) OR ( lie groups ))) or ( like groups ))) or ((((( linkage groups ) or ( link groups ))) or ( risk groups )))).
• Adding a wildcard symbol may retrieve word variants: (((((("life groups") OR ("lie groups"))) or ("like groups"))) or ((((("linkage groups") or ("link groups"))) or ("risk groups"))))*.