Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
van hanh » van thanh, ban hanh, van anh
toc sach » hoc sach, doc sach, thuoc sach
hieu ve » hieu va, hieu van
cham tu » pham tu, cam tu, chai tu
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, dua tren
ve cham » va cham, ve chat, vu cham
o lang » hoa lang, hoi lang
y lang » _ lang, tay lang, yen lang
tu van » tu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((y lang) or (o lang)) xa hoi. hieu ve cham tu van hanh di ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((y lang) OR (o lang)) xa hoi. hieu ve cham tu van hanh di ((cua tre) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: toc sach ((y lang) or (o lang)) xa hoi. hieu ve cham tu van hanh di ((cua tre) or (cua triet))*.