Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
ban thanh » ban hanh, ban hang
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
cac cuu » cap cuu, cac chu, cac cua
cac cau » cac mau, bac cau, ca cau
buu tre » cuu tre
hieu ve » hieu va, hieu van
cao hoc » co hoc, cho hoc, chat hoc

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) or (thu sach)) ky nang cao hoc. hieu ve ((cac cuu) OR (cac cau)) ban thanh tai buu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang cao hoc. hieu ve ((cac cuu) OR (cac cau)) ban thanh tai buu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang cao hoc. hieu ve ((cac cuu) OR (cac cau)) ban thanh tai buu tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang cao hoc. hieu ve ((cac cuu) OR (cac cau)) ban thanh tai buu tre*.