Perhaps you should try some spelling variations:
thu san » thuy san, thu ban, phu san
hieu va » lieu va, hieu qua
cac toc » cac toi, cac nuoc, cac thoi
va hanh » van hanh, va thanh, va danh
san ky » sang ky, van ky, dan ky
toc va » hoc va, toc ta, tuc va
vi cua » vai cua, di cua
x hoi » o hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu san ky nang ((x hoi) OR (xa hoi)). hieu va cac toc va hanh ((vi cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu san ky nang ((x hoi) OR (xa hoi)). hieu va cac toc va hanh ((vi cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu san ky nang ((x hoi) OR (xa hoi)). hieu va cac toc va hanh ((vi cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: thu san ky nang ((x hoi) OR (xa hoi)). hieu va cac toc va hanh ((vi cua) or (dai cua)) tre*.