Perhaps you should try some spelling variations:
nghiem thuoc » nghiem duoc, nghiem hoa, nghi thuc
thi nghiem » thuc nghiem
khach thi » khac thi, khach trai, quach thi
thuoc hoc » thuoc ho, thuoc nhom, thuong hoc
nghe duoc » nghiem duoc, che duoc
nghe nuoi » nghe noi, nghe moi
vu khach » vu khanh, vay khach, cua khach
vu khac » vu kham, vu khanh, bui khac

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( vu khach thi nghiem thuoc hoc ) or ( vu khac trai ((nghe duoc) OR (nghe nuoi)) hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( vu khach thi nghiem thuoc hoc ) OR ( vu khac trai ((nghe duoc) OR (nghe nuoi)) hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( vu khach thi nghiem thuoc hoc ) or ( vu khac trai ((nghe duoc) OR (nghe nuoi)) hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( vu khach thi nghiem thuoc hoc ) or ( vu khac trai ((nghe duoc) OR (nghe nuoi)) hoc ))*.