Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dinh vai » dinh van, dinh vi, dinh tai
ty hang » ly hang, thi hang, thu hang
hieu ve » hieu va, hieu van
dinh va » dinh van, dinh ve, tinh va
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
xuc va » duc va, tuc va, luc va

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