Perhaps you should try some spelling variations:
changed since » changes since, change since, change science
when changed » when change, been changed, we changed
yi chang » ii chang, ying chang, jin chang
quo when » do when, so when, quo been
wong siu » wong shiu, kong siu, wong sau
yi gang » ii gang, i gang, li gang

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: yang ((yi chang) OR (yi gang)) quo when changed since ((wang zhi) OR (wong siu)) ;~.
• Adding a wildcard symbol may retrieve word variants: yang ((yi chang) or (yi gang)) quo when changed since ((wang zhi) or (wong siu)) ;*.