Perhaps you should try some spelling variations:
hieu suat » hieu luat, hieu qua
sang tai » hang tai, sang tao, tang tai
phat duc » pham duc, phan duc, phan duoc
ky sang » ky nang, ky dang, ky tang
tai roi » lai roi, tai hoi, tai loi
hieu su » hieu sau, tieu su, hieu qua
va hanh » van hanh, va thanh, va danh
hieu so » thieu so
tu sac » tu sach, tu cac, tu san
vi cua » vai cua, di cua
sac ky » cac ky, sai ky
cua te » cua tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky sang tai roi. ((((hieu su) or (hieu so))) or (hieu suat)) phat duc va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky sang tai roi. ((((hieu su) OR (hieu so))) OR (hieu suat)) phat duc va hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: tu sac ky sang tai roi. ((((hieu su) or (hieu so))) or (hieu suat)) phat duc va hanh vi cua te*.