Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
hieu va » lieu va, hieu qua
nam tuc » nam thuc, nam truc, nam tu
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
tuc va » thuc va, truc va, tuc xa
vi cuu » vi luu, vinh cuu
x hoi » xa hoi, x ho, 5 hoi
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: tu sac ky nang ((x hoi) OR (o hoi)). ((hieu van) or (hieu va)) nam tuc va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang ((x hoi) OR (o hoi)). ((hieu van) OR (hieu va)) nam tuc va hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang ((x hoi) OR (o hoi)). ((hieu van) or (hieu va)) nam tuc va hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang ((x hoi) OR (o hoi)). ((hieu van) or (hieu va)) nam tuc va hanh vi cuu tre*.