Perhaps you should try some spelling variations:
"all-ireland under-21 world champions" » "all-ireland under-21 world championship", "all-ireland under-21 bowl champions", "all-ireland under-21 norm champions", "all-ireland under-21 world championships", "all-ireland defender-21 world champions", "all-ireland under-1 world champions", "all-ireland under-2 world champions", "all-ireland under-11 world champions"
"all-ireland under-21 worlds champion" » "all-ireland under-21 worldwide champion", "all-ireland defender-21 worlds champion", "all-ireland under-2 worlds champion", "all-ireland under-1 worlds champion", "all-ireland under-11 worlds champion"
"all-ireland under-21 world champion" » "all-ireland under-21 world championship", "all-ireland defender-21 world champion", "all-ireland under-1 world champion", "all-ireland under-2 world champion", "all-ireland under-11 world champion"

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: (("all-ireland under-21 world champions") OR ((("all-ireland under-21 world champion") OR ("all-ireland under-21 worlds champion")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"all-ireland under-21 world champions\") or (((\"all-ireland under-21 world champion\") OR (\"all-ireland under-21 worlds champion\"))))".
• Removing quotes may allow a broader search: (( all-ireland under-21 world champions ) or ((( all-ireland under-21 world champion ) OR ( all-ireland under-21 worlds champion )))).
• Adding a wildcard symbol may retrieve word variants: (("all-ireland under-21 world champions") or ((("all-ireland under-21 world champion") OR ("all-ireland under-21 worlds champion"))))*.