Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
hanh vai » hanh vi, hanh va, hanh tai
ban hanh » ban hang
vai cua » dai cua, hai cua, lai cua
dua ban » dia ban, cua ban, qua ban
cam dua » ca dua, cay dua, chay dua
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va
lang xa » lang ha, dang xay, lang van
y lang » o lang, _ lang, tay 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) or (thuoc sach)) y lang xa hoi. ((hieu va) OR (hieu qua)) cam dua ban hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) y lang xa hoi. ((hieu va) OR (hieu qua)) cam dua ban hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thuoc sach)) y lang xa hoi. ((hieu va) OR (hieu qua)) cam dua ban hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuoc sach)) y lang xa hoi. ((hieu va) OR (hieu qua)) cam dua ban hanh vai cua tre*.