Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
sach ky » sach y, sach ty, sach kem
cua tre » cua te, cua triet, dua tren
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
cao hoi » cau hoi, co hoi, cao hoc
cuu tre » cau tren, cau treo
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ky) OR (sac ky)) nang cao hoi. hieu ve cham thuc day hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sac ky)) nang cao hoi. hieu ve cham thuc day hanh vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) OR (sac ky)) nang cao hoi. hieu ve cham thuc day hanh vi ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) OR (sac ky)) nang cao hoi. hieu ve cham thuc day hanh vi ((cua tre) or (cuu tre))*.