Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
hanh doi » thanh doi, hanh noi, hang doi
sach thu » sach thue, sach thieu, sach tham
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
doi cua » dai cua, hoi cua
va cham » va chat, va tham
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, xach tay
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach thu)) ((nang xa) OR (nang ma)) hoi. hieu va cham thuc day hanh doi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) OR (sach thu)) ((nang xa) or (nang ma)) hoi. hieu va cham thuc day hanh doi cua tre~".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) OR (sach thu)) ((nang xa) or (nang ma)) hoi. hieu va cham thuc day hanh doi cua tre*.