Perhaps you should try some spelling variations:
sach tham » sach nha
tham nang » nham nang, tham lang, tham nhung
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
tham duc » pham duc, tham du, than duc
tan hanh » tan thanh, tang hanh, toan hanh
hanh lai » hanh lam, hanh tai, thanh lap
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
co hoi » co hoc
lai va » loai va, mai va, dai va
x hoi » xa hoi, o hoi, x ho

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 tham nang ((x hoi) or (((co hoi) OR (co loi)))). hieu van tham duc tan hanh lai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tham nang ((x hoi) OR (((co hoi) OR (co loi)))). hieu van tham duc tan hanh lai va triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach tham nang ((x hoi) or (((co hoi) OR (co loi)))). hieu van tham duc tan hanh lai va triet*".