Perhaps you should try some spelling variations:
mai khoi » mai khoa, tai khoa, cac khoi
tinh dat » tinh da, dinh dat, tinh dau
te sach » toc sach
sach ky » sac ky, sach y, sach ty
mai hoi » dai hoi, lai hoi, mai doi
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va tinh » may tinh
dat cua » dai cua, day cua, mat cua
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: te sach ky nang ((mai hoi) or (mai khoi)). hieu va cac duc va tinh dat cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((mai hoi) OR (mai khoi)). hieu va cac duc va tinh dat cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ((mai hoi) or (mai khoi)). hieu va cac duc va tinh dat cua tre*.