Perhaps you should try some spelling variations:
cham duc » pham duc, cham soc, pham duy
hanh tai » thanh tai, hang tai, han tai
ky lang » ky nang, ky dang, ky tang
hieu va » lieu va, hieu qua
va cham » va chat, va tham
va hanh » van hanh, va thanh, va danh
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
te bai » te bao, te tai, te ban
bai ky » ban ky, sai ky, bac ky
va hoi » va hoc, va hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: te bai ky lang ((va hoi) or (xa hoi)). hieu va cham duc va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te bai ky lang ((va hoi) OR (xa hoi)). hieu va cham duc va hanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: te bai ky lang ((va hoi) or (xa hoi)). hieu va cham duc va hanh tai cua tre*.