Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh duc » thach duc, than duc, thinh duc
thanh dai » thanh hai, thanh tai, thanh dat
tao khoi » tao hoi, thao khoa, lao khoa
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cua tre » cuu tre, cua triet, dua tren
cua te » cua tu

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 ky nang ((tao khoi) or (cau hoi)). hieu van thanh duc va thanh dai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((tao khoi) OR (cau hoi)). hieu van thanh duc va thanh dai ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ((tao khoi) or (cau hoi)). hieu van thanh duc va thanh dai ((cua tre) or (cua te))*.