Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
sach ky » sach y, sach ty, sach kem
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
tang ma » mang may, tang van
sac ky » cac ky, sai 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 (sac ky)) ((tang 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 (sac ky)) ((tang 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 (sac ky)) ((tang ma) or (nang x)) hoi. hieu va cac duc va hanh di su triet*.