Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
hieu quan » lieu quan, thien quan, lien quan
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
dao ban » dao dan, tao ban, do ban
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 hoa. ((hieu quan) or (hieu qua)) tac ((dao ban) OR (dao van)) hanh vi 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 ban) OR (dao van)) hanh vi cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang ma hoa. ((hieu quan) or (hieu qua)) tac ((dao ban) OR (dao van)) hanh vi cua vat".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ma hoa. ((hieu quan) or (hieu qua)) tac ((dao ban) OR (dao van)) hanh vi cua vat*.