Perhaps you should try some spelling variations:
sach van » sach han, sach va, bach van
cau thuc » cuu thuc, can thuc, cau phuc
van hanh » van thanh, ban hanh, van anh
dieu cua » dieu tra
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
de cua » le cua, te cua
ban x » ban xu, ban _, ban 1
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: su sach van ban x hoi. hieu ve ((cau thuc) or (cau truc)) van hanh ((de cua) OR (dieu cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach van ban x hoi. hieu ve ((cau thuc) OR (cau truc)) van hanh ((de cua) OR (dieu cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach van ban x hoi. hieu ve ((cau thuc) or (cau truc)) van hanh ((de cua) OR (dieu cua)) tre".
• Adding a wildcard symbol may retrieve word variants: su sach van ban x hoi. hieu ve ((cau thuc) or (cau truc)) van hanh ((de cua) OR (dieu cua)) tre*.