Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
hanh dai » hanh tai, hanh dao, vanh dai
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
ve pham » vi pham, v pham, ve phan
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
sach ky » sac ky, sach y, sach ty
nang ma » sang ma, nang cao, mang may
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet

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 ((lang xa) or (((nang ma) or (tang ma)))) hoi. hieu ve pham thuc va hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((lang xa) OR (((nang ma) OR (tang ma)))) hoi. hieu ve pham thuc va hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((lang xa) or (((nang ma) or (tang ma)))) hoi. hieu ve pham thuc va hanh dai cua tre*.