Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
thanh di » thanh doi, thanh de, thanh do
thuc day » thuc dan, thuc vat
thuc va » thuc vat, thuc dan
sac ky » cac ky
di cua » dai cua, doi cua, de 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: thu ((sac ky) OR (sai ky)) nang x hoi. hieu van nam ((thuc va) or (thuc day)) thanh di cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sac ky) OR (sai ky)) nang x hoi. hieu van nam ((thuc va) OR (thuc day)) thanh di cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sac ky) OR (sai ky)) nang x hoi. hieu van nam ((thuc va) or (thuc day)) thanh di cua triet".
• Adding a wildcard symbol may retrieve word variants: thu ((sac ky) OR (sai ky)) nang x hoi. hieu van nam ((thuc va) or (thuc day)) thanh di cua triet*.