Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
cham duc » pham duc, cham soc, pham duy
su sach » so sach, vu sach
duc van » duc va, duc tan, duc manh
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
dai hoi » dai hoc, dai hai, dai moi
cai hoi » cau hoi, cai hoa, lai hoi
so sanh » do sanh
su tien » su kien, su hien, tu tieng
tai su » tai so, tai tu, lai su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sanh)) ky nang ((cai hoi) OR (dai hoi)). hieu ve cham duc van hanh tai su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sanh)) ky nang ((cai hoi) OR (dai hoi)). hieu ve cham duc van hanh tai su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sanh)) ky nang ((cai hoi) OR (dai hoi)). hieu ve cham duc van hanh tai su tien".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sanh)) ky nang ((cai hoi) OR (dai hoi)). hieu ve cham duc van hanh tai su tien*.