Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
danh vai » danh sai, danh va, doanh van
hieu va » lieu va, hieu qua
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
cau luc » cau truc, cau phuc
so sach » so sanh, bo sach, co sach
dang xa » dang xay, dang ha, dang va
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
va cau » van cau, va cac, va dau
luc va » duc va, tuc va, loc va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (hoc sach)) y ((dang xa) OR (lang xa)) hoi. hieu va cau luc va danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (hoc sach)) y ((dang xa) OR (lang xa)) hoi. hieu va cau luc va danh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) or (hoc sach)) y ((dang xa) OR (lang xa)) hoi. hieu va cau luc va danh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (hoc sach)) y ((dang xa) OR (lang xa)) hoi. hieu va cau luc va danh vai cua tre*.