Perhaps you should try some spelling variations:
ban thanh » ban hanh
vu khach » vu khanh, vu khac, vay khach
khach ky » hanh ky, thanh ky
hieu van » hieu va, thien van, lieu va
ban hang » ngan hang
van dam » van nam, van dao, van dau
va hanh » van hanh, va thanh, va danh
su viet » so viet
dam tu » nam tu, cam tu, tam tu
ki su » ky su

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 ky nang x ho. hieu van dam tu ((((ban thanh) or (ban hang))) or (va hanh)) ki su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu khach ky nang x ho. hieu van dam tu ((((ban thanh) OR (ban hang))) OR (va hanh)) ki su viet.
• Adding a wildcard symbol may retrieve word variants: vu khach ky nang x ho. hieu van dam tu ((((ban thanh) or (ban hang))) or (va hanh)) ki su viet*.