Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
cuu tre » cua tre, cau tren, cau treo
danh di » danh du, xanh di, danh dien
va danh » va dinh, va dan, va hanh
cac dau » cac dan, cac du, cac dai
di cuu » di cau, di cua, dinh cuu
dau va » dau ve, lau va
vu sac » vu sach, vu san, va sac
sac ky » cac ky, sai ky
mo hoc » mon hoc, co hoc
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, o hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sac ky nang ((((o hoi) or (o hai))) or (mo hoc)). hieu vien cac dau va danh di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sac ky nang ((((o hoi) OR (o hai))) OR (mo hoc)). hieu vien cac dau va danh di cuu tre*.