Perhaps you should try some spelling variations:
tap nguoi » tay nguoi, gap nguoi, giap nguoi
tac nguoi » toc nguoi, tay nguoi, thuc nguoi
mach hoc » cach hoc, dich hoc, anh hoc
li nguoi » loi nguoi, le nguoi, ly nguoi
tu mach » tu cach, tu hach, tu sach
tu manh » tu minh, vu manh, tung manh
tu hanh » du hanh, lu hanh, thuc hanh
duoc li » duoc si, duoc ly, duoc lieu

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) OR (tu 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) OR (tu 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) OR (tu hanh)) duoc li nguoi ))".
• Adding a wildcard symbol may retrieve word variants: (( tu mach hoc ((tap nguoi) or (tac nguoi)) ) or ( ((tu manh) OR (tu hanh)) duoc li nguoi ))*.