Perhaps you should try some spelling variations:
hanh than » hanh han, hanh nhan, hanh phan
than cua » nhan cua, thai cua, ban cua
van hanh » van thanh, ban hanh, van anh
hieu ve » hieu va, hieu van
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cuu tre, cua triet
tu sach » thu sach, su sach, te sach
nang o » nang co, nang ho, nang ro
ve cac » va cac, vien cac
tu ban » thu ban, te ban
tu sac » tu cac, tu san, tu bac
o lai » o lao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((tu sac) OR (tu sach))) or (tu ban)) ky nang o lai. hieu ve cac duc van hanh than cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((tu sac) OR (tu sach))) OR (tu ban)) ky nang o lai. hieu ve cac duc van hanh than cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((tu sac) OR (tu sach))) or (tu ban)) ky nang o lai. hieu ve cac duc van hanh than cua tre".
• Adding a wildcard symbol may retrieve word variants: ((((tu sac) OR (tu sach))) or (tu ban)) ky nang o lai. hieu ve cac duc van hanh than cua tre*.