Perhaps you should try some spelling variations:
"synchronize swimming" » "synchronize stemming"
"synchronism swimming" » "synchronism stemming", "synchronising swimming"
"synchronizing swimming" » "synchronizing stemming"
"synchronized swimming" » "synchronized stemming"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((((("synchronize swimming") OR ("synchronism swimming"))) or ("synchronizing swimming"))) or ("synchronized swimming"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((((("synchronize swimming") OR ("synchronism swimming"))) OR ("synchronizing swimming"))) OR ("synchronized swimming")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((((\"synchronize swimming\") OR (\"synchronism swimming\"))) or (\"synchronizing swimming\"))) or (\"synchronized swimming\"))".
• Removing quotes may allow a broader search: (((((( synchronize swimming ) OR ( synchronism swimming ))) or ( synchronizing swimming ))) or ( synchronized swimming )).
• Adding a wildcard symbol may retrieve word variants: (((((("synchronize swimming") OR ("synchronism swimming"))) or ("synchronizing swimming"))) or ("synchronized swimming"))*.