Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hanh thai » nhanh thai, hinh thai, hanh tai
van hanh » van thanh, ban hanh, van anh
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cuu tre, dua tren
duc van » duc va, duc tan, duc manh
sach ky » sac ky, sach ty, sach kem
hieu ve » hieu va, hieu van
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) OR (cua triet))~.
• 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) OR (cua triet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (sach y)) nang o hoi. hieu ve cac duc van hanh thai ((cua tre) OR (cua triet))*".