Perhaps you should try some spelling variations:
hang thai » hoang thai, hang tai, hang hai
hieu van » hieu va, thien van, lieu va
nam duoc » nam thuoc, da duoc, dat duoc
tan hang » tan khang, ban hang, van hang
thai cua » than cua, tai cuc, tri cua
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cuu tre, cua triet
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky tang xa hoi. hieu van ((nam duoc) or (cao duc)) tan hang thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky tang xa hoi. hieu van ((nam duoc) OR (cao duc)) tan hang thai cua tre.
• Adding a wildcard symbol may retrieve word variants: su sac ky tang xa hoi. hieu van ((nam duoc) or (cao duc)) tan hang thai cua tre*.