Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
sai ky » sac ky
di su » doi su, ki su, da su

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 ma) or (nang x)) hoi. hieu va cac duc va hanh di su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sai ky)) ((nang ma) OR (nang x)) hoi. hieu va cac duc va hanh di su triet.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sai ky)) ((nang ma) or (nang x)) hoi. hieu va cac duc va hanh di su triet*.