Perhaps you should try some spelling variations:
thuat sac » thuat sach, thuat san, thuat tac
hieu quan » lieu quan, thien quan, lien quan
van hanh » van thanh, ban hanh, van anh
nang ma » tang ma, sang ma, nang cao
hac dao » hoc dao, tac dao, hat dao
dao van » do van, dang van
sac ky » cac ky, sai ky
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 sac ky nang ma hoi. ((hieu quan) or (hieu qua)) hac dao van hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sac ky nang ma hoi. ((hieu quan) OR (hieu qua)) hac dao van hanh vi cua vat.
• Adding a wildcard symbol may retrieve word variants: thuat sac ky nang ma hoi. ((hieu quan) or (hieu qua)) hac dao van hanh vi cua vat*.