Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van bao » van ban, van dao
su sach » so sach, vu sach
ly hang » ly quang
ly nang » ky nang, ly vang, ly quang
cua tre » cua te, cuu tre, cua triet
co hoi » co hoc, co loi
luc va » duc va, tuc va
loc va » hoc va
vi cua » vai cua, di cua

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

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