Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
ban thanh » ban hanh, ban hang
cay phoi » cap phoi, cay cho, gap phoi
tu sach » thu sach, su sach, te sach
ve cham » va cham, ve chat, vu cham
duc ban » duc tan, duc van, dua ban
sach ky » sac ky, sach y, sach ty
tay hoi » tay ho, tao hoi, tay thai
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
ve cam » ve cac, va cam, ve cai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky dang ((cay phoi) or (tay hoi)). hieu ((ve cam) OR (ve cham)) duc ban thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ((cay phoi) OR (tay hoi)). hieu ((ve cam) OR (ve cham)) duc ban thanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ((cay phoi) or (tay hoi)). hieu ((ve cam) OR (ve cham)) duc ban thanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((cay phoi) or (tay hoi)). hieu ((ve cam) OR (ve cham)) duc ban thanh dai cua tre*.