Perhaps you should try some spelling variations:
vien cac » vien bach, vien da, gian cac
vien dai » hien dai
thu sach » tu sach, thuat sach, thuoc sach
hanh tai » thanh tai, hang tai, han tai
tan hanh » tan thanh, tang hanh, toan hanh
tai cua » thai cua, tai cuc, tri cua
tu cach » tu cac
nang ma » tang ma, sang ma, nang cao
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 cach) or (thu sach)) ky nang ma hoi. hieu ((vien cac) or (vien dai)) duc tan hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (thu sach)) ky nang ma hoi. hieu ((vien cac) OR (vien dai)) duc tan hanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (thu sach)) ky nang ma hoi. hieu ((vien cac) or (vien dai)) duc tan hanh tai cua tre*.