Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu va » hieu qua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
van ha » van hoa, van chat, van hanh
ha cua » hoa cua, hai cua, nha cua
x hoi » xa hoi, o hoi, x ho
nuoc » quoc, duoc, ngoc

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 y nang x hoi. ((hieu va) or (lieu va)) dat nuoc va van ha cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang x hoi. ((hieu va) OR (lieu va)) dat nuoc va van ha cua tre*.