Perhaps you should try some spelling variations:
dang xay » dang van
thuc dan » thuc hanh, thuc vat
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
hanh ca » hanh cac, hanh cat, hanh cua
va can » va chan, va cac, va cao
ca cua » co cua
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 y ((dang xay) or (van xay)) hoi. hieu va can ((thuc dan) OR (hoc dan)) hanh ca cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((dang xay) OR (van xay)) hoi. hieu va can ((thuc dan) OR (hoc dan)) hanh ca cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((dang xay) or (van xay)) hoi. hieu va can ((thuc dan) OR (hoc dan)) hanh ca cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((dang xay) or (van xay)) hoi. hieu va can ((thuc dan) OR (hoc dan)) hanh ca cua te*.