Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
van tuan » van quan, anh tuan
ban hanh » ban hang
hanh dai » hanh tai, hanh dao, vanh dai
su sach » so sach, vu sach
duc ban » duc tan, duc van, dua ban
x hoi » o hoi, x ho, 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: su sach thu nang ((x hoi) or (xa hoi)). hieu ((van tuan) OR (van ban)) duc ban hanh dai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thu nang ((x hoi) OR (xa hoi)). hieu ((van tuan) OR (van ban)) duc ban hanh dai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thu nang ((x hoi) or (xa hoi)). hieu ((van tuan) OR (van ban)) duc ban hanh dai cua triet".
• Adding a wildcard symbol may retrieve word variants: su sach thu nang ((x hoi) or (xa hoi)). hieu ((van tuan) OR (van ban)) duc ban hanh dai cua triet*.