Perhaps you should try some spelling variations:
phase changed » phase change, has changed, have changed
changed over » changes over, change over
study phase » study phases, study case, study has
yang study » yang judy, arg study
yan yang » yang yang, yao yang, dan yang
chang ha » chang mae
hong yu » wong yue
wang » wing, wan

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: (wang OR lang) yan yang study phase changed over ((chang ha) OR (hong yu)) ;~.
• Adding a wildcard symbol may retrieve word variants: (wang or lang) yan yang study phase changed over ((chang ha) or (hong yu)) ;*.