Perhaps you should try some spelling variations:
thuc nguoi » toc nguoi
nguoi san » nguoi tay, nguoi dao, nguoi ma
hanh di » hanh de, hang di, danh di
cua tre » cuu tre, cua triet, dua tren
hieu de » hieu ve, hieu he, hieu le
de thuc » den thuc, do thuc, ve thuc
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky
nang o » nang co, nang ho, nang ro
cua te » cua tu
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky nang o hoi. hieu de thuc nguoi san ((hanh di) OR (hanh vi)) ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky nang o hoi. hieu de thuc nguoi san ((hanh di) OR (hanh vi)) ((cua tre) OR (cua te))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky nang o hoi. hieu de thuc nguoi san ((hanh di) OR (hanh vi)) ((cua tre) or (cua te))*".