Perhaps you should try some spelling variations:
challenges using » challenges during, challenges arising, challenges facing
using hyoung » using your, wang hyoung, using ground
hyoung hai » hong hai
wang yang » wang yan, wang liang, wang yanling
2 current » 3 current
yang xi » yang di, yang yi, yang jui
ong yet » ong yew, ong ye, wong yee
yet 2 » yet _, yet a, et 2

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))ong yet 2 current challenges using hyoung hai ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((wang yang) OR (yang xi))ong yet 2 current challenges using hyoung hai ;.
• Adding a wildcard symbol may retrieve word variants: ((wang yang) or (yang xi))ong yet 2 current challenges using hyoung hai ;*.