Perhaps you should try some spelling variations:
thanh va » thanh van, hanh va, thanh ha
thanh ve » hanh ve, thanh vien, thanh van
toc sac » toc sach, toc san, hoc sach
duc van » duc va, duc tan, duc manh
cao duc » dao duc, cao suc, giao duc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
tang xa » trang xa, lang xa, tang ha
sac ky » cac ky, sai ky
ve cao » va cao, ve bao, ve cac

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

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