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
so sach » so sanh, bo sach, co sach
hieu ve » hieu va, hieu van
ve cau » ke cau, va cau, ve cac
de cua » te cua, dieu cua
le cua » ly cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach van nang x hoi. hieu ve cau thuc van hanh ((de cua) or (le cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach van nang x hoi. hieu ve cau thuc van hanh ((de cua) OR (le cua)) tre.
• Adding a wildcard symbol may retrieve word variants: so sach van nang x hoi. hieu ve cau thuc van hanh ((de cua) or (le cua)) tre*.