Perhaps you should try some spelling variations:
dan thanh » dang thanh, danh thanh, ban thanh
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan, thuc vat
thanh di » thanh doi, thanh de, thanh do
te sach » toc sach
hieu ve » hieu va
cua tre » cua te, cuu tre, cua triet
te sac » te cac, te san
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sac) or (te sach)) ky nang x ho. ((hieu ve) OR (hieu van)) nam thuc dan thanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sac) OR (te sach)) ky nang x ho. ((hieu ve) OR (hieu van)) nam thuc dan thanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sac) or (te sach)) ky nang x ho. ((hieu ve) OR (hieu van)) nam thuc dan thanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sac) or (te sach)) ky nang x ho. ((hieu ve) OR (hieu van)) nam thuc dan thanh di cua tre*.