Perhaps you should try some spelling variations:
ban hanh » ban hang
canh tay » canh tac, thanh tay, anh ta
cau hoc » cau hoi, cau hoa, cao hoc
hoc ban » hoc bang, hoc dan, hoc bai
hieu ke » hieu kem, chieu ke, hieu ky
lang ha » long ha
ke cau » ket cau
di cua » doi cua, de cua, do cua

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: tu ((xach tay) OR (canh tay)) lang ha noi. hieu ke cau hoc ban hanh ((di cua) OR (dai cua)) te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((xach tay) or (canh tay)) lang ha noi. hieu ke cau hoc ban hanh ((di cua) OR (dai cua)) te~".
• Adding a wildcard symbol may retrieve word variants: tu ((xach tay) or (canh tay)) lang ha noi. hieu ke cau hoc ban hanh ((di cua) OR (dai cua)) te*.