Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu van » thien van, lieu va, hieu ve
dang van » hoang van, hang va
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
dao van » do van
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach ky nang ma hoi. ((hieu van) or (hieu va)) hac ((dao van) OR (dang van)) hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang ma hoi. ((hieu van) OR (hieu va)) hac ((dao van) OR (dang van)) hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang ma hoi. ((hieu van) or (hieu va)) hac ((dao van) OR (dang van)) hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ma hoi. ((hieu van) or (hieu va)) hac ((dao van) OR (dang van)) hanh vi cua vat*.