Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh oai
thanh dat » thanh san, thanh hai, thanh van
so sach » so sanh, bo sach, co sach
va cham » va chat, va tham
sach ty » sach y, sach tu, sach thu
ve cham » ve chat, vu cham, ve chim
mang xa » lang xa, mang may, dang xay
ty mang » ty xang, ty hang, tin mang
cua tre » cua te, cuu tre, cua triet
cuu ve » cuu va

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 ty mang xa hoi. hieu ((ve cham) or (va cham)) cuu ve ((thanh dai) OR (thanh dat)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty mang xa hoi. hieu ((ve cham) OR (va cham)) cuu ve ((thanh dai) OR (thanh dat)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty mang xa hoi. hieu ((ve cham) or (va cham)) cuu ve ((thanh dai) OR (thanh dat)) cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ty mang xa hoi. hieu ((ve cham) or (va cham)) cuu ve ((thanh dai) OR (thanh dat)) cua tre*.