Perhaps you should try some spelling variations:
dan hang » ban hang, van hang, dat hang
thuc dan » thuc hanh, hoc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
dang xay » dang van, van xay
hieu ve » hieu va, hieu van
te sach » toc sach
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
so sanh » do sanh
vi cau » va cau, di cau, viet cau
ve cau » ke cau, va cau, ve cac
ve nam » he nam, va nam, le nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (so sanh)) ky dang xay hoi. hieu ve nam thuc dan hang ((vi cau) OR (ve cau)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (so sanh)) ky dang xay hoi. hieu ve nam thuc dan hang ((vi cau) OR (ve cau)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (so sanh)) ky dang xay hoi. hieu ve nam thuc dan hang ((vi cau) OR (ve cau)) tren".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (so sanh)) ky dang xay hoi. hieu ve nam thuc dan hang ((vi cau) OR (ve cau)) tren*.