Perhaps you should try some spelling variations:
thanh phan » thanh pho, thanh san, thanh toan
cua viet » ca viet, hoa viet, cua vat
phan cua » nhan cua, than cua, phat cua
hieu van » hieu va, thien van, lieu va
duc ban » duc tan, dua ban, duc man
duc van » duc va, duc tan, duc manh
sac ky » cac ky, sai ky
su sac » su sach, su cac, su xac
o hoc » co hoc, mo hoc, so hoc
o hoi » co hoi, o hai, o hoa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky nang ((o hoi) OR (o hoc)). hieu van nam ((duc ban) OR (duc van)) thanh phan cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky nang ((o hoi) OR (o hoc)). hieu van nam ((duc ban) or (duc van)) thanh phan cua viet~".
• Adding a wildcard symbol may retrieve word variants: su sac ky nang ((o hoi) OR (o hoc)). hieu van nam ((duc ban) or (duc van)) thanh phan cua viet*.