Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
cau luc » cau truc, cau phuc
luc van » luoc van, luu van, duc van
cua tre » cua te, cuu tre, cua triet
te cac » tu cac, ve cac, te cao
ve cau » ke cau, va cau, ve cac
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 cac ky ((mang may) or (lang xa)) hoi. hieu ve cau luc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te cac ky ((mang may) OR (lang xa)) hoi. hieu ve cau luc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: te cac ky ((mang may) or (lang xa)) hoi. hieu ve cau luc van hanh vi cua tre*.