Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
thuc dan » thuc hanh, thuc vat
tu sach » thu sach, su sach, te sach
hoi dan » hoa dan, hoi dap, thoi dai
hanh ve » hanh vi, hanh va
hieu va » lieu va, hieu qua
va cau » van cau, va cac, va dau
cua te » cua tu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((hoi dan) OR (hoc dan)) xa hoi. hieu va cau thuc dan ((hanh ve) OR (hanh kem)) cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((hoi dan) OR (hoc dan)) xa hoi. hieu va cau thuc dan ((hanh ve) or (hanh kem)) cua te~".
• Adding a wildcard symbol may retrieve word variants: tu sach ((hoi dan) OR (hoc dan)) xa hoi. hieu va cau thuc dan ((hanh ve) or (hanh kem)) cua te*.