Perhaps you should try some spelling variations:
cua viet » ca viet, cua vat, cua dieu
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
hieu he » hieu ve, hiem he, hieu le
ty tang » tay tang, ty xang, ty hang
he nam » ha nam, nghe nam
ma hoi » mai hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty tang ((ma hoi) or (xa hoi)). hieu he nam thuc day hanh vi ((cua viet) OR (hoa viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty tang ((ma hoi) OR (xa hoi)). hieu he nam thuc day hanh vi ((cua viet) OR (hoa viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty tang ((ma hoi) or (xa hoi)). hieu he nam thuc day hanh vi ((cua viet) OR (hoa viet))".
• Adding a wildcard symbol may retrieve word variants: so sach ty tang ((ma hoi) or (xa hoi)). hieu he nam thuc day hanh vi ((cua viet) OR (hoa viet))*.