Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
sieu viet » su viet, dien viet, bien viet
van thanh » van tuan
ban thanh » ban hanh, ban hang
viet cac » vien cac, viet ca, viet bac
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
cac vo » cac co, cac vi, cac bo
via su » va su, gia su
x hoi » xa hoi, o hoi, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach ky nang ((x hoi) or (x ho)). sieu viet cac vo ((van thanh) OR (ban thanh)) via su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang ((x hoi) OR (x ho)). sieu viet cac vo ((van thanh) OR (ban thanh)) via su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach ky nang ((x hoi) or (x ho)). sieu viet cac vo ((van thanh) OR (ban thanh)) via su triet".
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ((x hoi) or (x ho)). sieu viet cac vo ((van thanh) OR (ban thanh)) via su triet*.