Perhaps you should try some spelling variations:
hanh thai » nhanh thai, hinh thai, hanh tai
may nang » may nong, ky nang, cam nang
thai cua » than cua, tai cuc, tri cua
thuc dan » thuc hanh, hoc dan, thuc vat
canh may » canh tay, hanh may, mang may
so canh » so sanh, bo canh, so danh
thuc va » thuc vat, thuc day
ve phan » va phan, ke phan, ve phat
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: so canh may nang ((x hoi) or (o hoi)). hieu ve phan ((thuc va) OR (thuc dan)) hanh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so canh may nang ((x hoi) OR (o hoi)). hieu ve phan ((thuc va) OR (thuc dan)) hanh thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so canh may nang ((x hoi) or (o hoi)). hieu ve phan ((thuc va) OR (thuc dan)) hanh thai cua tre".
• Adding a wildcard symbol may retrieve word variants: so canh may nang ((x hoi) or (o hoi)). hieu ve phan ((thuc va) OR (thuc dan)) hanh thai cua tre*.