Perhaps you should try some spelling variations:
tang khu » tai khu, tang ha, tang thi
cac duc » cac du, cac dac, cac nuoc
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cuu tre, cua triet
tang ky » dang ky, trong ky
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((tang ky) OR (tang khu)) lang xa hoi. hieu ve ((cac duc) or (cao duc)) va hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((tang ky) OR (tang khu)) lang xa hoi. hieu ve ((cac duc) OR (cao duc)) va hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((tang ky) OR (tang khu)) lang xa hoi. hieu ve ((cac duc) or (cao duc)) va hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: so ((tang ky) OR (tang khu)) lang xa hoi. hieu ve ((cac duc) or (cao duc)) va hanh va cua tre*.