Perhaps you should try some spelling variations:
nghiem dan » nghiem ban, nghiem van, nghiem dau
khac thai » khac trai, khac thi, khach trai
nghe duoc » nghiem duoc, nghe nuoi, che duoc
duoc hoc » quoc hoi
phai thi » pham thi, phap thi, hai thi
phan thi » pham thi, tran thi, phan tu
tu khac » vu khac, su khac, ta khac
dan hoc » van hoc, dan toc, dai hoc

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 thai nghe duoc hoc ) or ( tu ((phai thi) OR (phan thi)) nghiem dan hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu khac thai nghe duoc hoc ) OR ( tu ((phai thi) OR (phan thi)) nghiem dan hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu khac thai nghe duoc hoc ) or ( tu ((phai thi) OR (phan thi)) nghiem dan hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu khac thai nghe duoc hoc ) or ( tu ((phai thi) OR (phan thi)) nghiem dan hoc ))*.