Perhaps you should try some spelling variations:
tap nguoi » tay nguoi, gap nguoi, giap nguoi
tac nguoi » toc nguoi, tay nguoi, thuc nguoi
manh duoc » nganh duoc, doanh duoc, tranh duoc
hanh duoc » hanh thuoc, nganh duoc, doanh duoc
mach hoc » cach hoc, dich hoc, anh hoc
li nguoi » loi nguoi, le nguoi, ly nguoi
tu mach » tu cach, tu manh, tu hach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu mach hoc ((tap nguoi) or (tac nguoi)) ) or ( tu ((manh duoc) OR (hanh duoc)) li nguoi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu mach hoc ((tap nguoi) OR (tac nguoi)) ) OR ( tu ((manh duoc) OR (hanh duoc)) li nguoi )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu mach hoc ((tap nguoi) or (tac nguoi)) ) or ( tu ((manh duoc) OR (hanh duoc)) li nguoi ))".
• Adding a wildcard symbol may retrieve word variants: (( tu mach hoc ((tap nguoi) or (tac nguoi)) ) or ( tu ((manh duoc) OR (hanh duoc)) li nguoi ))*.