Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
so sach » so sanh, co sach, hoc sach
bo sach » co sach, hoc sach
xang xa » lang xa, mang xa, ang xa
van hoc » van hoa
hoc duc » hoc duoc, hoc nuoc, hoc thuc
su tien » su kien, su hien, tu tieng
vi su » va su, ve su, ki su

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) OR (bo sach)) ty xang xa hoi. hieu van hoc duc ((ban hanh) or (van ban)) vi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (bo sach)) ty xang xa hoi. hieu van hoc duc ((ban hanh) OR (van ban)) vi su tien*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) OR (bo sach)) ty xang xa hoi. hieu van hoc duc ((ban hanh) or (van ban)) vi su tien*".