Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, van bac
cac tuc » cac toc, cac tu, cac tac
xa hanh » xa thanh, xa khanh, va hanh
vai cua » hai cua, lai cua, bai cua
co hoi » co hoc, co loi

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: vu sach ky nang ((x ho) OR (co hoi)). hieu van cac tuc xa hanh ((vai cua) OR (dai cua)) te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang ((x ho) or (co hoi)). hieu van cac tuc xa hanh ((vai cua) OR (dai cua)) te~".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang ((x ho) or (co hoi)). hieu van cac tuc xa hanh ((vai cua) OR (dai cua)) te*.