Perhaps you should try some spelling variations:
may nguoi » tay nguoi, ma nguoi, lay nguoi
dau nguoi » dao nguoi, dau nguon, phau nguoi
hanh hoc » thanh hoc, hinh hoc, anh hoc
co nguoi » cho nguoi, con nguoi, o nguoi
benh hoc » sinh hoc
tu hoach » thu hoach, tu hach, quy hoach
hoach ha » hoach va, hoach xay, hoach hoi
tu hanh » tu thanh, du hanh, lu hanh
hoc dau » hoc dan, hoc dai, hoc dat
hoc co » hoc cao
ha may » nha may, hoa may, ha tay

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((( tu hanh hoc co nguoi ) or ( tai benh hoc dau nguoi ))) or ( tu hoach ha may nguoi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( tu hanh hoc co nguoi ) OR ( tai benh hoc dau nguoi ))) OR ( tu hoach ha may nguoi )).
• Adding a wildcard symbol may retrieve word variants: (((( tu hanh hoc co nguoi ) or ( tai benh hoc dau nguoi ))) or ( tu hoach ha may nguoi ))*.