Perhaps you should try some spelling variations:
nghiem duoc » nghiem thuoc, nghe duoc
thi nghiem » thuc nghiem
nghiem ad » nghiem d, nghiem ban, nghiem lam
thanh tai » thanh hai, thanh toan, doanh tai
khac thi » khau thi, khuc thi, khuat thi
thai tai » thai tay, thap tai, thai tran
duoc hoc » quoc hoi
tu khac » vu khac, su khac, ta khac

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

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