Perhaps you should try some spelling variations:
sach van » sach han, sach va, bach van
van nang » van quang, van ban, van dong
ban hanh » ban hang
thuc ban » thuoc ban, thuc dan, thu ban
can thuc » dan thuc, van thuc, cay thuc
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
hieu ve » hieu va
de cua » le cua, dieu cua
te cua » tue cua, le 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) OR (hieu van)) can thuc ban hanh ((de cua) or (te cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach van nang x hoi. ((hieu ve) OR (hieu van)) can thuc ban hanh ((de cua) OR (te cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach van nang x hoi. ((hieu ve) OR (hieu van)) can thuc ban hanh ((de cua) or (te cua)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach van nang x hoi. ((hieu ve) OR (hieu van)) can thuc ban hanh ((de cua) or (te cua)) tre*.