Perhaps you should try some spelling variations:
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
cam thuc » am thuc, nam thuc, cam thu
sach ky » sach y, sach ty, sach kem
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
nang xa » lang xa, nang ma, mang xa
ve cam » ve cham, ve cac, va cam
sac ky » cac ky, sai ky
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) OR (sac ky)) ((nang xa) OR (nang x)) hoi. hieu ve cam thuc day hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) ((nang xa) OR (nang x)) hoi. hieu ve cam thuc day hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) ((nang xa) OR (nang x)) hoi. hieu ve cam thuc day hanh vi cua tre*.