Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
su triet » su viet, su tien, ve triet
vu khach » vu khanh, vu khac, vay khach
hieu van » hieu va, thien van, lieu va
va danh » va dinh, va dan, va hanh
vu sach » vu bach, su sach
van cau » van dau, van hau, van chat
cau tu » dau tu, cau truc
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 sach) OR (vu khach)) ky nang x ho. hieu van cau tu ((ban thanh) or (va danh)) ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (vu khach)) ky nang x ho. hieu van cau tu ((ban thanh) OR (va danh)) ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) OR (vu khach)) ky nang x ho. hieu van cau tu ((ban thanh) or (va danh)) ki su triet".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) OR (vu khach)) ky nang x ho. hieu van cau tu ((ban thanh) or (va danh)) ki su triet*.