Perhaps you should try some spelling variations:
ha nghiem » khao nghiem, thi nghiem, thu nghiem
dao nghe » day nghe, da nghe, dat nghe
hoach ha » hoach va, hoach xay, hoach hoi
tu sach » thu sach, su sach, tu cach
te sach » toc sach
nghe de » nghe det, nghe di, nghe te
de hoc » te hoc, du hoc, dien hoc
su hoc » du hoc, so hoc, su ho
tu hoc » te 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 sach) OR (te sach)) dao nghe de hoc ) or ( thu hoach ha nghiem ((su hoc) or (tu hoc)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((tu sach) OR (te sach)) dao nghe de hoc ) OR ( thu hoach ha nghiem ((su hoc) OR (tu hoc)) ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((tu sach) OR (te sach)) dao nghe de hoc ) or ( thu hoach ha nghiem ((su hoc) or (tu hoc)) ))*".