Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach ty
hanh va » hang va, hanh vi
cac dac » cac dan, cac dai, cac bac
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
cac duc » cac du, cao duc, cac nuoc
va cua » va chua, via cua, ca cua

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 ((nang xa) or (lang xa)) hoi. hieu van ((cac duc) OR (cac dac)) van hanh va cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (lang xa)) hoi. hieu van ((cac duc) OR (cac dac)) van hanh va cua triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) or (lang xa)) hoi. hieu van ((cac duc) OR (cac dac)) van hanh va cua triet*".