Perhaps you should try some spelling variations:
cam thuc » nam thuc, cam thu, can thuc
sach thu » sach thue, sach thieu, sach tham
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, xach tay
xang xa » lang xa, mang xa, ang xa
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua

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)) xang xa hoi. hieu va ((cam thuc) OR (am thuc)) va hanh di cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) or (sach thu)) xang xa hoi. hieu va ((cam thuc) OR (am thuc)) va hanh di cua tre~".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) or (sach thu)) xang xa hoi. hieu va ((cam thuc) OR (am thuc)) va hanh di cua tre*.