Perhaps you should try some spelling variations:
va hanh » van hanh, va thanh, va danh
cao duc » dao duc, cao suc, giao duc
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
sai ky » sac ky
dat su » sat su
va cao » va cac, va co, va dao
x hoi » xa hoi, o hoi, x ho
de su » den su, ve su, de tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sai ky)) nang x hoi. hieu va cao duc va hanh ((de su) or (dat su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sai ky)) nang x hoi. hieu va cao duc va hanh ((de su) OR (dat su)) triet.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sai ky)) nang x hoi. hieu va cao duc va hanh ((de su) or (dat su)) triet*.