Perhaps you should try some spelling variations:
"linkage groups" » "linkage group", "link groups"
"life groups" » "lie groups", "life group", "line groups"
"like groups" » "lie groups", "large groups", "crime groups"
"live groups" » "lie groups", "five 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 ("live groups")))).
• Removing quotes may allow a broader search: (( life groups ) or ((((( like groups ) or ( linkage groups ))) or ( live groups )))).
• Adding a wildcard symbol may retrieve word variants: (("life groups") or ((((("like groups") or ("linkage groups"))) or ("live groups"))))*.