Perhaps you should try some spelling variations:
mach hoc » cach hoc, dich hoc, anh hoc
cuu dong » cuu cong, cuu tong, cuu long
dong hoc » dong co, dong luc
hoc hang » hoc hanh, hoc bang, hoc tang
hang hoa » hang khoa, thanh hoa, hang va
su mach » su sach
hoa dau » hoa dan, hoa dam, hoa cau
hoa dai » hoa dan, hoc dai
hoc xa » hoc ma
doan » doanh, dan, toan

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su mach hoc tap, nghien cuu dong hoc hang hoa hoc xa ((hoa dau) or (hoa dai)) chan doan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su mach hoc tap, nghien cuu dong hoc hang hoa hoc xa ((hoa dau) OR (hoa dai)) chan doan.
• Adding a wildcard symbol may retrieve word variants: su mach hoc tap, nghien cuu dong hoc hang hoa hoc xa ((hoa dau) or (hoa dai)) chan doan*.