Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cua viet » ca viet, hoa viet, cua vat
vien cac » vien bach, vien dai, vien da
sach ly » sach y, sach lo, sach ty
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
ly hang » ly quang
ve cac » va cac
va hoi » xa hoi, va hoc, va hoa

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 ly hang va hoi. hieu ((ve cac) or (vien cac)) thuyet va hanh vi ((cua viet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly hang va hoi. hieu ((ve cac) OR (vien cac)) thuyet va hanh vi ((cua viet) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: su sach ly hang va hoi. hieu ((ve cac) or (vien cac)) thuyet va hanh vi ((cua viet) or (su triet))*.