Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hoc duoc » hoc nuoc, hoa duoc, hoc dung
ban hanh » ban hang
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
hoc duc » hoc nuoc, hoc thuc, hoc dung
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 ty xang xa hoi. hieu van ((hoc duc) OR (hoc duoc)) ((ban hanh) or (van ban)) vi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty xang xa hoi. hieu van ((hoc duc) OR (hoc duoc)) ((ban hanh) OR (van ban)) vi su tien*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty xang xa hoi. hieu van ((hoc duc) OR (hoc duoc)) ((ban hanh) or (van ban)) vi su tien*".