Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
thu sach » tu sach, thuat sach, thuoc sach
danh vai » danh sai, danh va, doanh van
lang xa » lang ha, dang xay, lang van
cau duc » cao duc, cau luc, chu duc
va danh » va dinh, va dan, va hanh
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
sach o » sach lo, sac o, sach y
o lang » hoa lang, hoi lang

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 o 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: thu sach o lang xa hoi. ((hieu quan) OR (hieu qua)) cau duc va danh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach o lang xa hoi. ((hieu quan) or (hieu qua)) cau duc va danh vai cua tre*.