Perhaps you should try some spelling variations:
cua triet » cua viet, va triet
hanh sinh » hanh tinh, hanh dinh, hinh sinh
su triet » su viet, su tien, ve triet
cau thuc » cau truc, cuu thuc, can thuc
vat hanh » vat thanh, van hanh, va hanh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
van cau » van dau, van hau, van chat
tang o » trang o, lang o
xang o » lang o, dang o

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 tu ((xang o) or (tang o)) hoi. hieu van cau thuc vat hanh sinh ((cua triet) OR (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu ((xang o) OR (tang o)) hoi. hieu van cau thuc vat hanh sinh ((cua triet) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu ((xang o) or (tang o)) hoi. hieu van cau thuc vat hanh sinh ((cua triet) OR (su triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach tu ((xang o) or (tang o)) hoi. hieu van cau thuc vat hanh sinh ((cua triet) OR (su triet))*.