Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
vu khach » vu khanh, vu khac, vay khach
khach ky » hanh ky, thanh ky
hieu van » hieu va, thien van, lieu va
van chat » cao chat
su tien » su kien, tu tieng, dau tien
va danh » va dinh, va dan, va hanh
chat tu » nhat tu, chai tu, chay tu
su hien » su kien, thu hien, nhu hien

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