Perhaps you should try some spelling variations:
van nghiem » van nghe, van nghia, quang nghiem
hoach van » hoach va, hoach san, hoach toan
sach dat » sach dao, sach danh, sach bai
dat nghe » day nghe, da nghe, dang nghe
tu sach » thu sach, su sach, te sach
nghe ad » nghe adn, nghe cad, nghe ar
so hoc » co hoc, mo hoc, so hoa
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 dat nghe ad hoc ) or ( thu hoach van nghiem ((su ho) or (so hoc)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach dat nghe ad hoc ) OR ( thu hoach van nghiem ((su ho) OR (so hoc)) )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach dat nghe ad hoc ) or ( thu hoach van nghiem ((su ho) or (so hoc)) ))*.