Perhaps you should try some spelling variations:
day thanh » dao thanh, dat thanh, da thanh
cam thuc » am thuc, nam thuc, cam thu
day hanh » day nhanh, dao hanh, day manh
sach ky » sac ky, sach ty, sach kem
tai cua » thai cua, tai cuc, tri cua
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam

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 ky) or (sach y)) nang xa hoi. hieu ve cam thuc ((day hanh) OR (day thanh)) tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach y)) nang xa hoi. hieu ve cam thuc ((day hanh) OR (day thanh)) tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sach y)) nang xa hoi. hieu ve cam thuc ((day hanh) OR (day thanh)) tai cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach y)) nang xa hoi. hieu ve cam thuc ((day hanh) OR (day thanh)) tai cua tre*.