Perhaps you should try some spelling variations:
challenges caused » challenges case, challenges chapter, challenges call
recent challenges » present challenges, recent changes, treatment challenges
caused among » clausus among, use among, uses among
among tai » among team, among a, among di
yang xi » yang di, yang yi, yang jui
wang » wing, wan, lang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((wang yanling) or (yang xi))ng ((a a) OR (a la)) recent challenges caused among tai ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((wang yanling) OR (yang xi))ng ((a a) OR (a la)) recent challenges caused among tai ;*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((wang yanling) or (yang xi))ng ((a a) OR (a la)) recent challenges caused among tai ;*".