Perhaps you should try some spelling variations:
ha nghiem » khao nghiem, thi nghiem, thu nghiem
sach dao » lanh dao
dao nghe » day nghe, da nghe, dat nghe
hoach ha » hoach va, hoach xay, hoach hoi
tu sach » thu sach, su sach, te sach
nghe d » nghe di, nghe _, nghe 新
du hoc » tu hoc, duoc hoc
so hoc » co hoc, mo hoc, so hoa
d hoc » ad hoc, de hoc, y hoc
su ho » su hoa, su hoc, su pho

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 dao nghe d hoc ) or ( thu hoach ha nghiem ((((du hoc) or (su ho))) or (so hoc)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach dao nghe d hoc ) OR ( thu hoach ha nghiem ((((du hoc) OR (su ho))) OR (so hoc)) )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach dao nghe d hoc ) or ( thu hoach ha nghiem ((((du hoc) or (su ho))) or (so hoc)) ))*.