Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
thuc day » thuc dan, thuc vat
day hanh » day nhanh, day thanh, dao hanh
su sach » so sach, vu sach
mang xa » lang xa, mang may, dang xay
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
di cua » dai cua, doi cua, de cua

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 y ((mang xa) or (nang ma)) hoi. hieu ve cam thuc day hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((mang xa) OR (nang ma)) hoi. hieu ve cam thuc day hanh di cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach y ((mang xa) or (nang ma)) hoi. hieu ve cam thuc day hanh di cua tre*.