Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
doi cua » dai cua, hoi cua
va tinh » may tinh
van cac » van hac, van cau, van bac
su sach » so sach, vu sach
va nang » van nang, da nang, cam nang
so sanh » do sanh
cac tu » cac thu, cach tu, cac du
di cua » dai cua, de cua, do cua
x hoi » xa hoi, o hoi, x ho

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 sanh)) va nang x hoi. hieu van cac tu va tinh ((di cua) OR (doi cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sanh)) va nang x hoi. hieu van cac tu va tinh ((di cua) OR (doi cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sanh)) va nang x hoi. hieu van cac tu va tinh ((di cua) OR (doi cua)) tre*.