Perhaps you should try some spelling variations:
"synchronised swimming" » "synchronized swimming", "synchronism swimming"
"synchronised stemming" » "synchronized stemming", "synchronism stemming", "synchronised steering", "synchronised flemming", "synchronised stepping"
"synchronised streaming" » "synchronized streaming", "synchronism streaming"
"synchronised treating" » "synchronized treating", "synchronism treating", "synchronised creating", "synchronised heating", "synchronised relating"
"synchronize swimming" » "synchronized swimming", "synchronism swimming", "synchronizing swimming"
"synchronising treating" » "synchronising creating", "synchronising heating", "synchronising relating", "synchronizing treating", "synchronism treating", "synchronisations treating"

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: (((("synchronised swimming") OR ("synchronize swimming"))) OR ((("synchronised stemming") OR ((("synchronised streaming") OR ((("synchronised treating") OR ("synchronising treating"))))))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"synchronised swimming\") or (\"synchronize swimming\"))) or (((\"synchronised stemming\") or (((\"synchronised streaming\") or (((\"synchronised treating\") OR (\"synchronising treating\"))))))))~".
• Removing quotes may allow a broader search: (((( synchronised swimming ) or ( synchronize swimming ))) or ((( synchronised stemming ) or ((( synchronised streaming ) or ((( synchronised treating ) OR ( synchronising treating ))))))))~.
• Adding a wildcard symbol may retrieve word variants: (((("synchronised swimming") or ("synchronize swimming"))) or ((("synchronised stemming") or ((("synchronised streaming") or ((("synchronised treating") OR ("synchronising treating"))))))))*.