Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thu sach » tu sach, thuat sach, thuoc sach
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
tu cach » tu cac
cac xuc » cam xuc, chat xuc, cac cuoc
hieu ve » hieu va, hieu van
ky tang » ky nang, ky dang, kho tang
tang ma » mang may, tang van
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (thu sach)) ky tang ma hoi. hieu ve ((cac xuc) or (cac nuoc)) van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (thu sach)) ky tang ma hoi. hieu ve ((cac xuc) OR (cac nuoc)) van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (thu sach)) ky tang ma hoi. hieu ve ((cac xuc) or (cac nuoc)) van hanh vi cua tre*.