Perhaps you should try some spelling variations:
mai khoi » mai khoa, tai khoa, cac khoi
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
hanh va » hang va, hanh vi
xuc van » duc van, luc van, vuc van
hieu va » lieu va, hieu qua
dai hoi » dai hoc, dai hai, dai moi
cua duc » cua tuc, cua nuoc, cua quoc
lai hoi » lai hoa, lai roi, mai hoi
y nang » ky nang, ly nang, v nang
va cam » va cham, va cac, va cao
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang ((mai khoi) or (((lai hoi) or (dai hoi)))). hieu va cam xuc van hanh va cua duc~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((mai khoi) OR (((lai hoi) OR (dai hoi)))). hieu va cam xuc van hanh va cua duc.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((mai khoi) or (((lai hoi) or (dai hoi)))). hieu va cam xuc van hanh va cua duc*.