Perhaps you should try some spelling variations:
concurrent challenges » current challenges, concurrent changes, concerns challenges
yang xi » yang di, yang jui
yang yi » yang di, yang jui
1 dang » 1 dan, 1 daring, 1 dating
ng a » lng a, ngo a, png a
wang » wing, wan
hai » hadi, haji, hari

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) or (((yang xi) or (yang yi))))ng a 3 concurrent challenges 1 dang hai ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((wang OR lang) yan) OR (((yang xi) OR (yang yi))))ng a 3 concurrent challenges 1 dang hai ;.
• Adding a wildcard symbol may retrieve word variants: (((wang or lang) yan) or (((yang xi) or (yang yi))))ng a 3 concurrent challenges 1 dang hai ;*.