Perhaps you should try some spelling variations:
thanh va » thanh van, thanh ha, thanh ve
hanh va » hang va, hanh vi
cao duc » dao duc, cao suc, giao duc
sach ky » sach y, sach ty, sach kem
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
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: vu ((sach ky) or (sac ky)) lang xa hoi. hieu ve cao duc va ((thanh va) OR (hanh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach ky) OR (sac ky)) lang xa hoi. hieu ve cao duc va ((thanh va) OR (hanh va)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu ((sach ky) or (sac ky)) lang xa hoi. hieu ve cao duc va ((thanh va) OR (hanh va)) cua tre*".