Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nang tai » hang tai, tang tai, sang tai
so sach » so sanh, bo sach, co sach
tai cua » thai cua, tai cuc, tri cua
va nang » van nang, da nang, cam nang
cac tuc » cac toc, cac tu, cac tac
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va
la quan » va quan, luat quan, van quan
ly quan » ly quang, ly luan, ly qua
tuc va » thuc va, truc va, tuc xa

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 ((ly quan) OR (la quan)) xa hoi. ((hieu ve) or (hieu van)) cac tuc va nang tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ly quan) OR (la quan)) xa hoi. ((hieu ve) OR (hieu van)) cac tuc va nang tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((ly quan) OR (la quan)) xa hoi. ((hieu ve) or (hieu van)) cac tuc va nang tai cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ((ly quan) OR (la quan)) xa hoi. ((hieu ve) or (hieu van)) cac tuc va nang tai cua tre*.