Perhaps you should try some spelling variations:
sach hoa » sach ha, sach hoi, bach hoa
thuc dan » thuc hanh, hoc dan
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
hanh ve » hanh vi, hanh va
dan xa » dan xac, dan xay, dan ca
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.

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