Perhaps you should try some spelling variations:
van thiet » va thiet, dan thiet, can thiet
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
hieu ve » hieu va
chao tu » chao xu, cho tu, cao tu
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi

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 ty xang xa hoi. ((hieu ve) or (hieu van)) chao tu va hanh va van thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty xang xa hoi. ((hieu ve) OR (hieu van)) chao tu va hanh va van thiet.
• Adding a wildcard symbol may retrieve word variants: su sach ty xang xa hoi. ((hieu ve) or (hieu van)) chao tu va hanh va van thiet*.