Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
va thanh » ban thanh, va tinh, le thanh
cau luc » cau truc, cau phuc
lam cua » nam cua, lam chat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cau duc » cao duc, chu duc, cau truc
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang o hoi. hieu van ((cau duc) OR (cau luc)) ((va thanh) or (gia thanh)) lam cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoi. hieu van ((cau duc) OR (cau luc)) ((va thanh) OR (gia thanh)) lam cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hoi. hieu van ((cau duc) OR (cau luc)) ((va thanh) or (gia thanh)) lam cua triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang o hoi. hieu van ((cau duc) OR (cau luc)) ((va thanh) or (gia thanh)) lam cua triet*.