Perhaps you should try some spelling variations:
dang nguoi » dung nguoi, nang nguoi, tang nguoi
dao nguoi » cho nguoi
mach hoc » cach hoc, dich hoc, anh hoc
sach hoi » sach doi, sach moi, cach thoi
hoi dang » hoi dan, hoi lang, hoi dong
hoc dao » hoc dan, hoc cao, hoc dai
su sach » so sach, vu sach
tim » time

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tim mach hoc dao nguoi ) or ( su sach hoi dang nguoi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tim mach hoc dao nguoi ) OR ( su sach hoi dang nguoi )).
• Adding a wildcard symbol may retrieve word variants: (( tim mach hoc dao nguoi ) or ( su sach hoi dang nguoi ))*.