Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
hoc sach » hoc sinh, hoc cac, hoc anh
ty hang » ly hang, thi hang, thu hang
van cam » van nam, van lam, van cau
cam luc » cam xuc, cau luc
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va
va cua » va chua, via cua, ca cua

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

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