Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh dat, thanh oai
thanh tai » thanh hai, thanh toan, doanh tai
toc sach » hoc sach, doc sach, thuoc sach
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
ty hang » ly hang, ty xang, thi hang
cua tre » cua te, cuu tre, cua triet
hang x » nang x, hoang xa, chang xu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ty hang x hoi. hieu va cac duc va ((thanh dai) or (thanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ty hang x hoi. hieu va cac duc va ((thanh dai) OR (thanh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ty hang x hoi. hieu va cac duc va ((thanh dai) or (thanh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ty hang x hoi. hieu va cac duc va ((thanh dai) or (thanh tai)) cua tre*.