Perhaps you should try some spelling variations:
thanh dat » thanh san, thanh hai, thanh van
van thanh » ban thanh, van tuan
hieu van » hieu va, thien van, lieu va
tang cua » mang cua, hang cua, tang luan
luc van » luoc van, luu van, duc van
cac luc » cau luc, coc luc, cac nuoc
van cac » van hac, van cau, van bac
su sach » vu sach
cua moi » cua mot, cua hoi
do tang » de tang, do dang, cao tang
so sanh » do sanh
so sach » bo sach, co sach, hoc sach
su viet » so viet
dat su » sat su

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) OR (so sanh)))) do tang cua moi. hieu van cac luc van thanh dat su viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (((so sach) OR (so sanh)))) do tang cua moi. hieu van cac luc van thanh dat su viet~".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (((so sach) OR (so sanh)))) do tang cua moi. hieu van cac luc van thanh dat su viet*.