Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
sach thu » sach thieu, sach tham, cach thuc
xang xa » lang xa, mang xa, ang xa
hieu va » lieu va, hieu qua
cac duc » cac du, cac dac, cac nuoc
cao duc » dao duc, cao suc, giao duc
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
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: su ((sach thue) OR (sach thu)) xang xa hoi. hieu va ((cac duc) or (cao duc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach thue) OR (sach thu)) xang xa hoi. hieu va ((cac duc) OR (cao duc)) va hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach thue) OR (sach thu)) xang xa hoi. hieu va ((cac duc) or (cao duc)) va hanh vi cua tre*".