Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, nam thu, nam tu
hanh dai » hanh tai, hanh dao, vanh dai
sach va » sach ha, sach dao, sach nha
sach xa » sach dao, sach nha, sach bai
cao hoc » co hoc, cho hoc, chat hoc
va hanh » van hanh, va thanh, va danh

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 va) or (sach xa)) nang cao hoc. hieu van ((am thuc) or (nam thuc)) va hanh dai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach va) OR (sach xa)) nang cao hoc. hieu van ((am thuc) OR (nam thuc)) va hanh dai cua triet.
• Adding a wildcard symbol may retrieve word variants: su ((sach va) or (sach xa)) nang cao hoc. hieu van ((am thuc) or (nam thuc)) va hanh dai cua triet*.