Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh dao » lanh dao, thanh dat, thanh dam
hanh dai » hanh tai, vanh dai, thanh dat
su sach » vu sach
cac lop » cac hop, cac loai
van cac » van hac, van cau, van bac
hang xa » hoang xa, hang va, hang ca
ty hang » ly hang, ty xang, thi hang
so sach » so sanh, bo sach, co sach
cua duc » cua tuc, cua nuoc, cua quoc
lop va » lap va, hop va, nop va

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) OR (so sach)) ty hang xa hoi. hieu van cac lop va ((hanh dai) OR (hanh dao)) cua duc~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ty hang xa hoi. hieu van cac lop va ((hanh dai) OR (hanh dao)) cua duc~".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ty hang xa hoi. hieu van cac lop va ((hanh dai) OR (hanh dao)) cua duc*.