Perhaps you should try some spelling variations:
hoach dat » hoach xay, hoc dat, hoach va
hieu van » hieu va, thien van, hieu ve
thanh vi » hanh vi, thanh ve, nhanh vi
thanh va » thanh van, hanh va, thanh ha
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa

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 ky nang ma hoi. ((hieu van) or (lieu va)) hoach dat va ((thanh vi) or (thanh va)) cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. ((hieu van) OR (lieu va)) hoach dat va ((thanh vi) OR (thanh va)) cua vat.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. ((hieu van) or (lieu va)) hoach dat va ((thanh vi) or (thanh va)) cua vat*.