Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
va thanh » gia thanh, ban thanh, va tinh
te sach » toc sach
sach ky » sac ky, sach y, sach ty
tai cua » thai cua, tai cuc, tri cua
cac dac » cac dan, cac dai, cac bac
cac tac » cac toc, cac bac, cac tai
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
ma hoi » mai hoi, ma hoa, me hoi

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 dang ((ma hoi) or (xa hoi)). hieu ve ((cac tac) OR (cac dac)) va thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky dang ((ma hoi) OR (xa hoi)). hieu ve ((cac tac) OR (cac dac)) va thanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky dang ((ma hoi) or (xa hoi)). hieu ve ((cac tac) OR (cac dac)) va thanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky dang ((ma hoi) or (xa hoi)). hieu ve ((cac tac) OR (cac dac)) va thanh tai cua tre*.