Perhaps you should try some spelling variations:
khoa hoi » khoan hoi, khoa hoc, khoa doi
hanh doi » thanh doi, hanh noi, hang doi
xach tay » canh tay
van hanh » van thanh, ban hanh, van anh
sach tay » sach hay, sach nay, sach tai
che hoc » cho hoc, che ho, che thuoc
doi cua » dai cua, hoi cua
hoc van » hoc dan, hoc va, hoc vat
hieu ke » hieu kem, chieu ke, hieu ky
hoa hoi » hoa hoc, hoa doi, hoc hoi
ke che » ke he
cua te » cua tu

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 ((sach tay) OR (xach tay)) cong ((hoa hoi) OR (khoa hoi)). hieu ke che hoc van hanh doi cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach tay) or (xach tay)) cong ((hoa hoi) OR (khoa hoi)). hieu ke che hoc van hanh doi cua te~".
• Adding a wildcard symbol may retrieve word variants: tu ((sach tay) or (xach tay)) cong ((hoa hoi) OR (khoa hoi)). hieu ke che hoc van hanh doi cua te*.