Perhaps you should try some spelling variations:
tang mai » tang ma, tang tai, lang mai
ky tang » ky nang, ky dang, kho tang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu van
hieu va » lieu va, hieu qua
soc ban » coc ban, so ban, soc ba
hoc ban » hoc bang, hoc dan, hoc bai
cua tre » cua te, cuu tre, cua triet
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: tu cac ky tang mai hoi. ((hieu ve) OR (hieu va)) cham ((soc ban) OR (hoc ban)) hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky tang mai hoi. ((hieu ve) OR (hieu va)) cham ((soc ban) or (hoc ban)) hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu cac ky tang mai hoi. ((hieu ve) OR (hieu va)) cham ((soc ban) or (hoc ban)) hanh vi cua tre*.