Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach ty, sach kem
nam duc » nam duoc, pham duc, nam thuc
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ky) or (sach y)) nang ((x hoi) OR (x ho)). hieu van nam duc va hanh di cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sach y)) nang ((x hoi) OR (x ho)). hieu van nam duc va hanh di cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sach y)) nang ((x hoi) OR (x ho)). hieu van nam duc va hanh di cua triet".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sach y)) nang ((x hoi) OR (x ho)). hieu van nam duc va hanh di cua triet*.