Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hieu cua » hieu qua, dieu cua, bieu cua
van anh » van thanh, tuan anh, van minh
tu sach » thu sach, su sach, te sach
nang xa » lang xa, nang ma, mang xa
cac vuc » cac vung, cac cuoc, cac quoc
anh vi » hanh vi, anh va, anh ve
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (nang x)) hoi. hieu cua ((cac vuc) OR (cac nuoc)) van anh vi cua triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang xa) OR (nang x)) hoi. hieu cua ((cac vuc) or (cac nuoc)) van anh vi cua triet~".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) OR (nang x)) hoi. hieu cua ((cac vuc) or (cac nuoc)) van anh vi cua triet*.