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
sach ky » sac ky, sach y, sach ty
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
hat dao » hat dan, hat dam, hat do
dao van » do van, dang van
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) OR (tang ma)) hoa. ((hieu quan) or (hieu qua)) hat dao van hanh vi cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky ((nang ma) OR (tang ma)) hoa. ((hieu quan) OR (hieu qua)) hat dao van hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky ((nang ma) OR (tang ma)) hoa. ((hieu quan) or (hieu qua)) hat dao van hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky ((nang ma) OR (tang ma)) hoa. ((hieu quan) or (hieu qua)) hat dao van hanh vi cua vat*.