Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
nang noi » nang doc
vu sach » vu bach, su sach
noi hoi » noi doi, doi hoi, hoi hoi
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cac tu » cac thu, cach tu, cac du
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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

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