Perhaps you should try some spelling variations:
recent challenges » present challenges, recent changes, treatment challenges
challenges min » challenges m, challenges making, challenges moving
min hyoung » min hong, mun young
hyoung ghi » hyoung gun, hong ghi
wang yang » wang yan, wang liang, wang yanling
yang xi » yang di, yang yi, yang jui
ya a » a a, yu a, 1a a
ye a » yet a, e a, me a
y a » y la

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((wang yang) or (yang xi))ng ((((ya a) OR (ye a))) or (y a)) recent challenges min hyoung ghi ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((wang yang) OR (yang xi))ng ((((ya a) OR (ye a))) OR (y a)) recent challenges min hyoung ghi ;.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((wang yang) or (yang xi))ng ((((ya a) OR (ye a))) or (y a)) recent challenges min hyoung ghi ;".
• Adding a wildcard symbol may retrieve word variants: ((wang yang) or (yang xi))ng ((((ya a) OR (ye a))) or (y a)) recent challenges min hyoung ghi ;*.