Perhaps you should try some spelling variations:
cac truc » cau truc, cac tru, cac trung
su triet » su viet, ve triet
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
truc va » thuc va, thuc vat, trung va
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va
su tien » su kien, su hien, tu tieng
xang x » nang x
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 ty xang x hoi. ((hieu ve) or (hieu van)) cac truc va thanh vi ((su triet) OR (su tien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty xang x hoi. ((hieu ve) OR (hieu van)) cac truc va thanh vi ((su triet) OR (su tien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty xang x hoi. ((hieu ve) or (hieu van)) cac truc va thanh vi ((su triet) OR (su tien))".
• Adding a wildcard symbol may retrieve word variants: su sach ty xang x hoi. ((hieu ve) or (hieu van)) cac truc va thanh vi ((su triet) OR (su tien))*.