Perhaps you should try some spelling variations:
lua viet » luat viet, luan viet, cua viet
sua viet » su viet, cua viet, qua viet
hanh dai » hanh tai, hanh dao, vanh dai
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, nam thuc
tu sach » thu sach, su sach, te sach
hieu va » lieu va
tang ma » mang may, tang van
ky tang » ky nang, ky dang, kho tang
tuc va » thuc va, truc va, tuc xa
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 tang ma hoi. ((hieu va) or (hieu qua)) cam tuc va hanh dai ((sua viet) OR (lua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky tang ma hoi. ((hieu va) OR (hieu qua)) cam tuc va hanh dai ((sua viet) OR (lua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky tang ma hoi. ((hieu va) or (hieu qua)) cam tuc va hanh dai ((sua viet) OR (lua viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky tang ma hoi. ((hieu va) or (hieu qua)) cam tuc va hanh dai ((sua viet) OR (lua viet))*.