Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
kho tang » cao tang
hieu van » hieu va, thien van, lieu va
thanh va » thanh van, hanh va, thanh ha
te sach » toc sach
ky tang » ky nang, ky dang, ky trong
van bac » van ban, van bao, van hac
duc ban » duc van, dua ban, duc man
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: te sach ((ky tang) or (kho tang)) xa hoi. hieu van bac ((duc ban) OR (duc tan)) thanh va cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ky tang) OR (kho tang)) xa hoi. hieu van bac ((duc ban) OR (duc tan)) thanh va cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ky tang) or (kho tang)) xa hoi. hieu van bac ((duc ban) OR (duc tan)) thanh va cua triet".
• Adding a wildcard symbol may retrieve word variants: te sach ((ky tang) or (kho tang)) xa hoi. hieu van bac ((duc ban) OR (duc tan)) thanh va cua triet*.