Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
cham cua » chat cua, cham cuu, ham cua
sach ty » sach tu, sach thu, xach tay
hieu va » lieu va, hieu qua
va cham » va chat, va tham
cua tre » cua te, cuu tre, cua triet
va hoi » xa hoi, va hoc, va hoa

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

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