Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
ban hanh » ban hang
truc ban » thuc ban, truc dan, truc van
nang xa » nang x, nang ma, mang xa
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
hanh de » hanh ve, hanh kem
te sai » te tai, te bai, te lai
sai ky » sac ky
ve cau » ke cau, va cau, ve 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: te sai ky ((nang xa) OR (lang xa)) hoi. hieu ve cau truc ban hanh de ((cua tre) OR (cau tren))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sai ky ((nang xa) OR (lang xa)) hoi. hieu ve cau truc ban hanh de ((cua tre) or (cau tren))~".
• Adding a wildcard symbol may retrieve word variants: te sai ky ((nang xa) OR (lang xa)) hoi. hieu ve cau truc ban hanh de ((cua tre) or (cau tren))*.