Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van ban
cay phoi » cap phoi, tay hoi, cay cho
su sach » so sach, vu sach
van anh » van thanh, tuan anh, van minh
sach va » sach xa, sach ha, sach dao
hieu ve » hieu va, hieu van
xay hoi » xa hoi, tay hoi, gay thoi
va dang » van dang, va nang, va lang
ve cau » ke cau, va cau, ve cac
di cua » dai cua, doi cua, de cua
cua te » cua tu

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 va dang ((xay hoi) OR (cay phoi)). hieu ve cau truc ((van hanh) or (van anh)) di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach va dang ((xay hoi) OR (cay phoi)). hieu ve cau truc ((van hanh) OR (van anh)) di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach va dang ((xay hoi) OR (cay phoi)). hieu ve cau truc ((van hanh) or (van anh)) di cua te".
• Adding a wildcard symbol may retrieve word variants: su sach va dang ((xay hoi) OR (cay phoi)). hieu ve cau truc ((van hanh) or (van anh)) di cua te*.