Perhaps you should try some spelling variations:
dao nguoi » cho nguoi
lam nguoi » tay nguoi
hanh duoc » hanh thuoc, nganh duoc, doanh duoc
hach hoc » cach hoc, mach hoc, hoach hoi
le nguoi » ly nguoi, den nguoi, loi nguoi
tu hach » tu cach, tu sach, vu khach
tu hanh » du hanh, lu hanh, thuc hanh
duoc le » duoc ly, duoc li, 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 hach hoc ((lam nguoi) OR (dao nguoi)) ) or ( tu hanh duoc le nguoi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu hach hoc ((lam nguoi) OR (dao nguoi)) ) OR ( tu hanh duoc le nguoi )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu hach hoc ((lam nguoi) OR (dao nguoi)) ) or ( tu hanh duoc le nguoi ))".
• Adding a wildcard symbol may retrieve word variants: (( tu hach hoc ((lam nguoi) OR (dao nguoi)) ) or ( tu hanh duoc le nguoi ))*.