Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
sang ma » tang ma, nang ma, sang tao
van cam » van nam, van lam, van dam
van cau » van dau, van hau, van chat
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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 ky sang ma hoi. hieu ((van cam) OR (van cau)) tu va hanh vi ((cua tre) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky sang ma hoi. hieu ((van cam) OR (van cau)) tu va hanh vi ((cua tre) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky sang ma hoi. hieu ((van cam) OR (van cau)) tu va hanh vi ((cua tre) or (cua viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky sang ma hoi. hieu ((van cam) OR (van cau)) tu va hanh vi ((cua tre) or (cua viet))*.