Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
cam thuc » am thuc, cam thu, can thuc
hieu van » hieu va, thien van, lieu va
sach vu » sach tu, sach uu, sach xu
sach va » sach xa, sach ha, sach dao
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach vu) OR (sach va)) nang x hoi. hieu van ((cam thuc) or (nam thuc)) van hanh vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach vu) OR (sach va)) nang x hoi. hieu van ((cam thuc) OR (nam thuc)) van hanh vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach vu) OR (sach va)) nang x hoi. hieu van ((cam thuc) or (nam thuc)) van hanh vi cua triet".
• Adding a wildcard symbol may retrieve word variants: su ((sach vu) OR (sach va)) nang x hoi. hieu van ((cam thuc) or (nam thuc)) van hanh vi cua triet*.