Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
va danh » va dinh, va dan, dia danh
sach ty » sach y, sach tu, sach thu
va hanh » va thanh, ban hanh, dao hanh
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
ang xa » lang xa, mang xa, dang xay
ty ang » ty xang, ty hang, ty anh
de cua » le cua, te cua, dieu cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ty ang xa hoi. hieu va cam thuc ((((va hanh) or (va danh))) or (van hanh)) de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty ang xa hoi. hieu va cam thuc ((((va hanh) OR (va danh))) OR (van hanh)) de cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ty ang xa hoi. hieu va cam thuc ((((va hanh) or (va danh))) or (van hanh)) de cua tre*.