Perhaps you should try some spelling variations:
ty hoang » huy hoang, thi hoang, duy hoang
so sach » so sanh, bo sach, co sach
su tien » su kien, tu tieng, dau tien
hanh ve » hanh vi, hanh va, hanh kem
va hanh » van hanh, va thanh, va danh
cac luc » cau luc, coc luc, cac nuoc
hieu va » lieu va, hieu qua
van hoe » van hoa, van hoc, van hieu
ty hang » ly hang, ty xang, thi hang
su hien » su kien, thu hien, nhu hien
luc va » duc va, tuc va, loc va

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 ((ty hoang) or (ty hang)) van hoe. hieu va cac luc va hanh ve ((su tien) OR (su hien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ty hoang) OR (ty hang)) van hoe. hieu va cac luc va hanh ve ((su tien) OR (su hien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((ty hoang) or (ty hang)) van hoe. hieu va cac luc va hanh ve ((su tien) OR (su hien))".
• Adding a wildcard symbol may retrieve word variants: so sach ((ty hoang) or (ty hang)) van hoe. hieu va cac luc va hanh ve ((su tien) OR (su hien))*.