Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
dang khai » dang khoi, dang hai, quang khai
khai cua » thai cua, hai cua, khi cua
van dang » van dong, van dung, van nang
nuoc van » nuoc va, nuoc san, luoc van
thu sach » tu sach, thuat sach, thuoc sach
van bac » van ban, van bao, van hac
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, dan cac
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 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: thu sach ky nang ((x hoi) OR (o hoi)). thien ((van cac) or (van bac)) nuoc van dang khai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((x hoi) OR (o hoi)). thien ((van cac) OR (van bac)) nuoc van dang khai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((x hoi) OR (o hoi)). thien ((van cac) or (van bac)) nuoc van dang khai cua triet".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((x hoi) OR (o hoi)). thien ((van cac) or (van bac)) nuoc van dang khai cua triet*.