Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
danh sai » dung sai, danh bat, danh dau
danh vai » danh va, doanh van, dang van
tu sach » thu sach, su sach, te sach
cau duc » cao duc, cau luc, chu duc
sach lo » sach dao, sach doi, sach hoi
lang xa » lang ha, dang xay, lang van
lo lang » o lang, so lang, le lang
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: tu sach lo lang xa hoi. ((hieu quan) or (hieu qua)) cau duc va ((danh vai) or (danh sai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach lo lang xa hoi. ((hieu quan) OR (hieu qua)) cau duc va ((danh vai) OR (danh sai)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach lo lang xa hoi. ((hieu quan) or (hieu qua)) cau duc va ((danh vai) or (danh sai)) cua tre*.