Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
toc sach » hoc sach, doc sach, thuoc sach
thi hong » thi cong, thi phuong, thi hanh
tinh doi » trinh doc, trinh do, tinh hoc
doi cua » dai cua, hoi cua
va tinh » may tinh
cac luc » cau luc, coc luc, cac nuoc
van cac » van hac, van cau, van bac
luc va » duc va, tuc va, loc va
x hoi » xa hoi, o hoi, 5 hoi

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) thi hong ((x hoi) OR (x ho)). hieu van cac luc va tinh doi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) thi hong ((x hoi) OR (x ho)). hieu van cac luc va tinh doi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) thi hong ((x hoi) OR (x ho)). hieu van cac luc va tinh doi cua viet".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) thi hong ((x hoi) OR (x ho)). hieu van cac luc va tinh doi cua viet*.