Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hanh dai » hanh tai, hanh dao, vanh dai
sach ky » sac ky, sach ty, sach kem
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
dai su » dai sua, dai so, dan su
x hoi » xa hoi, x ho, 5 hoi
ve am » va am
o hoi » co hoi, o hoc, o hai

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 (sach y)) nang ((x hoi) or (o hoi)). hieu ve am thuc va hanh dai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang ((x hoi) OR (o hoi)). hieu ve am thuc va hanh dai su triet.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) nang ((x hoi) or (o hoi)). hieu ve am thuc va hanh dai su triet*.