Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
hanh tai » thanh tai, hang tai, han tai
viec cac » vien cac, viec cua, viec lam
cua tre » cua te, cuu tre, cua triet
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
cac duc » cac du, cao duc, cac dac
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
sang xa » song xa, lang xa, mang xa
sac ky » cac ky, sai ky
te sac » te sach, te cac, te san

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky ((sang xa) or (((sang ma) or (nang ma)))) hoi. hieu viec cac duc va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((sang xa) OR (((sang ma) OR (nang ma)))) hoi. hieu viec cac duc va hanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: te sac ky ((sang xa) or (((sang ma) or (nang ma)))) hoi. hieu viec cac duc va hanh tai cua tre*.