Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
co sach » bo sach, cuon sach, hoc sach
van cac » van hac, van cau, van bac
cac toc » cac toi, cac nuoc, cac thoi
tu hanh » du hanh, lu hanh, thuc hanh
hanh di » hanh vi, hanh de, hang di
toc tu » hoc tu, toc ta, tac tu
di su » doi su, ki su, da su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (co sach)) ky nang x ho. hieu van cac toc tu hanh di su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (co sach)) ky nang x ho. hieu van cac toc tu hanh di su triet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (co sach)) ky nang x ho. hieu van cac toc tu hanh di su triet*.