Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh di » thanh doi, thanh de, thanh do
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
tu sach » thu sach, su sach, tu cach
te sach » toc sach
cuu tre » cua tre, cau tren, cau treo
v nang » va nang, vu nang, van nang
y nang » ky nang, ly nang, may nang
ve cac » va cac, vien cac
cac tu » cac thu, cach tu, cac du
tu ban » thu ban, te ban
di cuu » di cau, di cua, dinh cuu

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