Perhaps you should try some spelling variations:
sach danh » sach tranh, sach dao, sach dung
va triet » va thiet, va trien, ve triet
xac danh » xac dinh, tac danh, cac doanh
tu sach » thu sach, su sach, te sach
hieu he » hieu ve, hiem he, hieu le
ky sang » ky dang, ky tang, duy sang
ma hoi » mai hoi, xa hoi, ma hoa
bat va » ban va, dat va, vat va
he nam » ha nam, nghe nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ky sang) OR (ky nang)) ma hoi. hieu he nam thu ((xac danh) or (sach danh)) bat va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky sang) OR (ky nang)) ma hoi. hieu he nam thu ((xac danh) OR (sach danh)) bat va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky sang) OR (ky nang)) ma hoi. hieu he nam thu ((xac danh) or (sach danh)) bat va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky sang) OR (ky nang)) ma hoi. hieu he nam thu ((xac danh) or (sach danh)) bat va triet*.