Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
dinh vai » dinh van, dinh vi, dinh va
thu sach » tu sach, thuat sach, thuoc sach
sach le » cach le, sach de, sach lo
cau duc » cao duc, cau luc, chu duc
va dinh » van dinh, va kinh, va tinh
le lang » le tang, le dang, le xang
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, va 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 le lang ((ha hoi) OR (xa hoi)). ((hieu quan) or (hieu qua)) cau duc va dinh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach le lang ((ha hoi) OR (xa hoi)). ((hieu quan) OR (hieu qua)) cau duc va dinh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach le lang ((ha hoi) OR (xa hoi)). ((hieu quan) or (hieu qua)) cau duc va dinh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach le lang ((ha hoi) OR (xa hoi)). ((hieu quan) or (hieu qua)) cau duc va dinh vai cua tre*.