Perhaps you should try some spelling variations:
than cua » nhan cua, thai cua, ban cua
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
nang o » nang co, nang ho, nang ro
tu can » tu ban, tu cac, thu canh
tu sac » tu sach, tu cac, tu san
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 can)) ky nang o lai. hieu ve cac du ((van hanh) OR (ban hanh)) than cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sac) OR (tu can)) ky nang o lai. hieu ve cac du ((van hanh) OR (ban hanh)) than cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sac) or (tu can)) ky nang o lai. hieu ve cac du ((van hanh) OR (ban hanh)) than cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sac) or (tu can)) ky nang o lai. hieu ve cac du ((van hanh) OR (ban hanh)) than cua tre*.