Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh hai » thanh phan, thanh hoa, thanh san
tu sach » thu sach, su sach, te sach
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cua triet, dua tren
duc van » duc va, duc tan, duc manh
cuu tre » cau tren, cau treo
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
tay hoi » tay ho, tao hoi, tay thai
ky dang » ky nang, ky danh
ve cac » va cac, vien cac

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: tu sach ky dang ((tay hoi) OR (y thai)). hieu ve cac duc van thanh hai ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ((tay hoi) or (y thai)). hieu ve cac duc van thanh hai ((cua tre) OR (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((tay hoi) or (y thai)). hieu ve cac duc van thanh hai ((cua tre) OR (cuu tre))*.