Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, hieu ve
thanh vi » hanh vi, thanh va, nhanh vi
thanh ve » hanh ve, thanh va, thanh vien
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hac dat » hoc dat, tac dat, hoach dat
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: thu sach ky nang ma hoi. ((hieu van) OR (lieu va)) hac dat va ((thanh vi) or (thanh ve)) cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ma hoi. ((hieu van) OR (lieu va)) hac dat va ((thanh vi) OR (thanh ve)) cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ma hoi. ((hieu van) OR (lieu va)) hac dat va ((thanh vi) or (thanh ve)) cua vat".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ma hoi. ((hieu van) OR (lieu va)) hac dat va ((thanh vi) or (thanh ve)) cua vat*.