Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu quan » lieu quan, thien quan, lien quan
van hanh » van thanh, ban hanh, van anh
hanh vai » hanh vi, hanh va, hanh tai
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
tac dao » toc dao, tac da, tac bao
dao van » do van, dang van
vai cua » dai cua, hai cua, lai 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 hoa. ((hieu quan) or (hieu qua)) tac dao van hanh vai cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang ma hoa. ((hieu quan) OR (hieu qua)) tac dao van hanh vai cua vat.
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ma hoa. ((hieu quan) or (hieu qua)) tac dao van hanh vai cua vat*.