Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cua viet » ca viet, hoa viet, cua vat
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cam tuc » cam tu, nam thuc, dam thuc
cua tre » cua te, cuu tre, cua triet
tu cai » tu cac, tu can, tu bai
cai ky » cao ky, cac ky, cam ky
ma hoi » mai hoi, xa hoi, ma hoa

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

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