Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
van hau » van ha, van hai, van dau
van cac » van hac, van cau, van bac
sach ty » sach tu, sach thu, xach tay
nang co » nang cao, nang doc, nang noi
cua tre » cua te, cuu tre, cua triet
co hoi » co hoc, co loi
bo van » vo van, so van, do van
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: te ((sach ty) OR (sach y)) nang co hoi. hieu ((van cac) or (van hau)) bo van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach y)) nang co hoi. hieu ((van cac) OR (van hau)) bo van hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) OR (sach y)) nang co hoi. hieu ((van cac) or (van hau)) bo van hanh vi cua tre*".