Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
sach tran » sach tranh, sach tren, vach tran
van hanh » van thanh, ban hanh, van anh
nam truc » nam truoc, nam thuc, nam trung
cam truc » cau truc, lam truoc, nam truoc
hieu ve » hieu va, hieu van
hanh te » hanh tu, hanh ve, hanh de
vu sach » vu bach, su sach, vu khach
te cua » tue cua, le cua, de cua
x hoi » o 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: vu sach tran quang ((x hoi) OR (xa hoi)). hieu ve ((cam truc) or (nam truc)) van hanh te cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach tran quang ((x hoi) OR (xa hoi)). hieu ve ((cam truc) OR (nam truc)) van hanh te cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach tran quang ((x hoi) OR (xa hoi)). hieu ve ((cam truc) or (nam truc)) van hanh te cua triet".
• Adding a wildcard symbol may retrieve word variants: vu sach tran quang ((x hoi) OR (xa hoi)). hieu ve ((cam truc) or (nam truc)) van hanh te cua triet*.