Perhaps you should try some spelling variations:
mai khoi » mai khoa, tai khoa, cac khoi
hanh lam » thanh lap, hanh kem, hanh va
tay tang » tay lang, tay trung, tay quang
van hanh » van thanh, ban hanh, van anh
cham duc » pham duc, cham soc, pham duy
lam cua » nam cua, lam chat
duc van » duc va, duc tan, duc manh
va cham » va chat, va tham
su sach » so sach
hieu va » lieu va, hieu qua
mai hoi » dai hoi, lai hoi, mai doi
vu sach » vu bach, vu khach
cua tre » cua te, cuu tre, cua triet

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 (vu sach)) tay tang ((mai hoi) OR (mai khoi)). hieu va cham duc van hanh lam cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) tay tang ((mai hoi) OR (mai khoi)). hieu va cham duc van hanh lam cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) tay tang ((mai hoi) OR (mai khoi)). hieu va cham duc van hanh lam cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) tay tang ((mai hoi) OR (mai khoi)). hieu va cham duc van hanh lam cua tre*.