Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
hanh lai » hanh lam, hanh tai, thanh lap
cua viet » ca viet, hoa viet, cua vat
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
va cham » va chat, va tham
duc ban » duc van, dua ban, duc man
lai cua » dai cua, hai cua, lai chau
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 cham ((duc ban) OR (duc tan)) 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 cham ((duc ban) OR (duc tan)) 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 cham ((duc ban) OR (duc tan)) hanh lai cua viet".
• Adding a wildcard symbol may retrieve word variants: su sach thu nang ((x hoi) or (xa hoi)). hieu va cham ((duc ban) OR (duc tan)) hanh lai cua viet*.