Perhaps you should try some spelling variations:
manh xay » nganh xay, dang xay, mang xa
sach le » cach le, sach de, sach kem
sach lo » sach dao, sach doi, sach hoi
hieu va » lieu va, hieu qua
cao duc » dao duc, cao suc, giao duc
va hanh » van hanh, va thanh, va danh
va cao » va cac, va co, va dao
vi va » vi van, vai va, vu va
thiet » thieu

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 le) OR (sach lo)) ((manh xay) or (van xay)) hoi. hieu va cao duc va hanh vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach le) OR (sach lo)) ((manh xay) OR (van xay)) hoi. hieu va cao duc va hanh vi va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach le) OR (sach lo)) ((manh xay) or (van xay)) hoi. hieu va cao duc va hanh vi va thiet".
• Adding a wildcard symbol may retrieve word variants: su ((sach le) OR (sach lo)) ((manh xay) or (van xay)) hoi. hieu va cao duc va hanh vi va thiet*.