Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
thu sach » tu sach, thuat sach, thuoc sach
hanh hai » thanh hai, nhanh hai, hang hai
sach le » cach le, sach de, sach lo
le lang » le tang, le dang, le xang
lang xa » lang ha, dang xay, lang van
cau duc » cao duc, cau luc, chu duc
va hanh » van hanh, va thanh, va danh
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet

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 xa hoi. ((hieu quan) or (hieu qua)) cau duc va hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach le lang xa hoi. ((hieu quan) OR (hieu qua)) cau duc va hanh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach le lang xa hoi. ((hieu quan) or (hieu qua)) cau duc va hanh hai cua tre*.