Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
ban thanh » ban hanh, ban hang
thanh de » hanh de, thanh ve, thanh do
thuc ban » thuoc ban, thuc dan, thu ban
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cua triet, dua tren
va pham » van pham, va phat, va phap
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, mang may
cuu tre » cau tren, cau treo

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: su sach ty ((nang ma) OR (nang cao)) hoi. hieu va pham thuc ban thanh de ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((nang ma) OR (nang cao)) hoi. hieu va pham thuc ban thanh de ((cua tre) or (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((nang ma) OR (nang cao)) hoi. hieu va pham thuc ban thanh de ((cua tre) or (cuu tre))*.