Perhaps you should try some spelling variations:
than soc » than hoc, than so, thanh son
ban hang » ngan hang
ky tang » ky nang, ky dang, kho tang
hang vi » hang va, hanh vi, hang di
cua tre » cua te, cuu tre, cua triet
te cac » tu cac, ve cac, te cao
ma hoi » mai hoi, ma hoa, me hoi
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te cac ky tang ((ma hoi) OR (xa hoi)). hieu qua ((than soc) OR (than doc)) ban hang vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te cac ky tang ((ma hoi) OR (xa hoi)). hieu qua ((than soc) or (than doc)) ban hang vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: te cac ky tang ((ma hoi) OR (xa hoi)). hieu qua ((than soc) or (than doc)) ban hang vi cua tre*.