Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
truc ban » thuc ban, truc dan, truc van
cua tre » cua te, cua triet, dua tren
hanh de » hanh ve, hanh kem
van cau » van dau, van hau, van chat
cuu tre » cau tren, cau treo
hoa hoi » khoa hoi, hoa hoc, hoa doi
ky lang » ky nang, ky dang, ky tang
bai ky » ban ky, sai ky, bac ky
ha hoi » ha noi, xa hoi, va hoi
te bai » te bao, te tai, te ban

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 bai ky lang ((ha hoi) OR (hoa hoi)). hieu van cau truc ban hanh de ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te bai ky lang ((ha hoi) OR (hoa hoi)). hieu van cau truc ban hanh de ((cua tre) or (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: te bai ky lang ((ha hoi) OR (hoa hoi)). hieu van cau truc ban hanh de ((cua tre) or (cuu tre))*.