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

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach da nghe d hoc ) or ( thu hoach ha nghiem ((su hoc) or (so hoc)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach da nghe d hoc ) OR ( thu hoach ha nghiem ((su hoc) OR (so hoc)) ))*.