Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
quoc ban » quoc bao, quoc lan, quoc quan
va triet » va thiet, va trien, ve triet
vu sach » vu bach, su sach, vu khach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
xuc ban » duc ban, cuc ban, xuat ban
ve cac » va cac, vien cac
vi va » vi van, vai va, vu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (vu sach)) ky nang xa hoi. hieu ve cac ((xuc ban) OR (quoc ban)) hanh vi va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (vu sach)) ky nang xa hoi. hieu ve cac ((xuc ban) OR (quoc ban)) hanh vi va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (vu sach)) ky nang xa hoi. hieu ve cac ((xuc ban) OR (quoc ban)) hanh vi va triet".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (vu sach)) ky nang xa hoi. hieu ve cac ((xuc ban) OR (quoc ban)) hanh vi va triet*.