Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
hieu van » hieu va, thien van, lieu va
ban duc » ban duoc, van duc, ban dac
tai cua » thai cua, tai cuc, tri cua
van anh » tuan anh, van minh
so sach » bo sach, co sach, hoc sach
ty nang » ky nang, ty xang, ty hang
so sanh » do sanh
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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 (so sanh)) ty nang x hoi. hieu van ban duc ((van anh) or (van thanh)) tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) ty nang x hoi. hieu van ban duc ((van anh) OR (van thanh)) tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) OR (so sanh)) ty nang x hoi. hieu van ban duc ((van anh) or (van thanh)) tai cua te".
• Adding a wildcard symbol may retrieve word variants: ((so sach) OR (so sanh)) ty nang x hoi. hieu van ban duc ((van anh) or (van thanh)) tai cua te*.