Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
thu nang » thi nang, thu hang, thu bang
hanh lai » hanh lam, hanh tai, thanh lap
sach thu » sach thue, sach thieu, sach tham
lai cua » dai cua, hai cua, lai chau
duc van » duc va, duc tan, duc manh
su sach » so sach, vu sach
duc ban » duc tan, dua ban, duc man
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
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 va tham ((duc ban) OR (duc van)) hanh lai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thu nang ((x hoi) OR (xa hoi)). hieu va tham ((duc ban) OR (duc van)) hanh lai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thu nang ((x hoi) or (xa hoi)). hieu va tham ((duc ban) OR (duc van)) hanh lai cua viet".
• Adding a wildcard symbol may retrieve word variants: su sach thu nang ((x hoi) or (xa hoi)). hieu va tham ((duc ban) OR (duc van)) hanh lai cua viet*.