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", "risk groups", "disk groups"
"lie groups" » "live groups", "line groups"

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