Perhaps you should try some spelling variations:
gat thanh » dat thanh, tat thanh, vat thanh
cac thuc » cach thuc, cac thu, can thuc
thuc gat » thuc vat, thuc giai, thuc hoat
su triet » su viet, ve triet
thanh vi » hanh vi, thanh va, thanh ve
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
van cac » van hac, van cau, van bac
su tien » su kien, su hien, tu tieng
x hoi » xa hoi, o hoi, 5 hoi

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) or (x ho)). hieu van cac thuc gat 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) OR (x ho)). hieu van cac thuc gat 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) or (x ho)). hieu van cac thuc gat thanh vi ((su triet) OR (su tien))".
• Adding a wildcard symbol may retrieve word variants: su sach ty xang ((x hoi) or (x ho)). hieu van cac thuc gat thanh vi ((su triet) OR (su tien))*.