Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
van hanh » van thanh, ban hanh, van anh
thai cua » than cua, tai cuc, tri cua
sach ky » sac ky, sach ty, sach kem
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
ve cac » va cac, vien cac
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ky) or (sach y)) nang o hoi. hieu ve cac duc van hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sach y)) nang o hoi. hieu ve cac duc van hanh thai cua tre.
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) or (sach y)) nang o hoi. hieu ve cac duc van hanh thai cua tre*.