Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
sach song » sach dung
danh vai » danh sai, danh va, doanh van
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
cau duc » cao duc, cau luc, chu duc
sach so » mach so, sach lo, sach dao
lang xa » lang ha, dang xay, lang van
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 so) OR (sach song)) lang xa hoi. ((hieu quan) or (hieu qua)) cau duc va danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach so) OR (sach song)) lang xa hoi. ((hieu quan) OR (hieu qua)) cau duc va danh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach so) OR (sach song)) lang xa hoi. ((hieu quan) or (hieu qua)) cau duc va danh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach so) OR (sach song)) lang xa hoi. ((hieu quan) or (hieu qua)) cau duc va danh vai cua tre*.