Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cuu tre, cua triet
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
hieu va » lieu va, hieu qua

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

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