Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
khach ty » sach ty
vu khach » vu khanh, vu khac, vay khach
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu van
duc van » duc va, duc tan, duc manh
ty nang » ky nang, ty xang, ty hang
vai cua » dai cua, hai cua, lai cua
hieu va » lieu va, hieu qua
nang o » nang co, nang ho, nang ro
vi cua » di cua
o hoc » co hoc, mo hoc, so hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu khach ty nang o hoc. ((hieu ve) or (hieu va)) cam duc van hanh ((vi cua) OR (vai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu khach ty nang o hoc. ((hieu ve) OR (hieu va)) cam duc van hanh ((vi cua) OR (vai cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu khach ty nang o hoc. ((hieu ve) or (hieu va)) cam duc van hanh ((vi cua) OR (vai cua)) triet".
• Adding a wildcard symbol may retrieve word variants: vu khach ty nang o hoc. ((hieu ve) or (hieu va)) cam duc van hanh ((vi cua) OR (vai cua)) triet*.