Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
ly quang » le quang, vu quang
van bac » van ban, van bao, van hac
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
x hoi » xa hoi, o hoi, x ho

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

• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ly hang) OR (ly quang)) x hoi. hieu van bac duc va thanh dai ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ly hang) or (ly quang)) x hoi. hieu van bac duc va thanh dai ((cua tre) OR (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ly hang) or (ly quang)) x hoi. hieu van bac duc va thanh dai ((cua tre) OR (cuu tre))*.