Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van giao » nang giao, toan giao, dan gian
va thanh » gia thanh, ban thanh, va tinh
su sach » vu sach
so sach » so sanh, bo sach, co sach
lo xang » le xang
xang xa » lang xa, mang xa, ang xa
va hanh » van hanh, va danh, ban hanh
hai va » hai van, thai va, hoi va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) OR (so sach)) lo xang xa hoi. hieu van giao duc ((va hanh) or (va thanh)) hai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) lo xang xa hoi. hieu van giao duc ((va hanh) OR (va thanh)) hai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (so sach)) lo xang xa hoi. hieu van giao duc ((va hanh) or (va thanh)) hai va thiet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (so sach)) lo xang xa hoi. hieu van giao duc ((va hanh) or (va thanh)) hai va thiet*.