Perhaps you should try some spelling variations:
sach van » sach han, sach va, bach van
van nang » van quang, van ban, van dong
cau thuc » cau truc, cuu thuc, can thuc
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
hanh de » hanh ve, hanh kem
cua tre » cuu tre, cua triet, dua tren
nang o » nang co, nang ho, nang ro
ve cau » ke cau, va cau, ve cac
cua te » cua tu
o hoc » co hoc, mo hoc, so hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach van nang o hoc. hieu ve cau thuc van hanh de ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach van nang o hoc. hieu ve cau thuc van hanh de ((cua tre) OR (cua te))*.