Perhaps you should try some spelling variations:
change theory » exchange theory, range theory, choice theory
change timor » change time, change timing, changed times
yang yang » wang yang, wang yan
wang hui » wang hua, wang zhi, wang wei
yan yan » yan yuan, nan yan, wang yan
hua can » hua ban, arua can, hua chen

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

• Performing a fuzzy search may retrieve terms with similar spellings: (wang or lang) ((yan yan) or (yang yang)) hua can ((change timor) OR (change theory)) wang hui ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (wang OR lang) ((yan yan) OR (yang yang)) hua can ((change timor) OR (change theory)) wang hui ;.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(wang or lang) ((yan yan) or (yang yang)) hua can ((change timor) OR (change theory)) wang hui ;".
• Adding a wildcard symbol may retrieve word variants: (wang or lang) ((yan yan) or (yang yang)) hua can ((change timor) OR (change theory)) wang hui ;*.