Perhaps you should try some spelling variations:
day nhanh » day thanh, duy nhanh, dac nhan
cham thuc » nham thuc, pham thuc, tham thuc
day hanh » day thanh, dao hanh, da hanh
day manh » van manh, duc manh, ha manh
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
di cua » dai cua, doi cua, de cua
vu sac » vu sach, vu san, va sac
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sac ky nang x hoi. hieu van cham thuc ((((day hanh) or (day manh))) or (day nhanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sac ky nang x hoi. hieu van cham thuc ((((day hanh) OR (day manh))) OR (day nhanh)) di cua tre.
• Adding a wildcard symbol may retrieve word variants: vu sac ky nang x hoi. hieu van cham thuc ((((day hanh) or (day manh))) or (day nhanh)) di cua tre*.