Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
dan thanh » dang thanh, danh thanh, ban thanh
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan, thuc vat
lang van » dang van, tang van, hoang van
cam thuc » am thuc, nam thuc, cam thu
doi cua » dai cua, hoi cua
van cam » van nam, van lam, van cau
so sanh » do sanh
lang xa » lang ha, dang xay
sanh y » sinh y, anh y, hanh y
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sanh y ((lang xa) or (lang van)) hoi. hieu van cam thuc dan thanh doi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh y ((lang xa) OR (lang van)) hoi. hieu van cam thuc dan thanh doi cua tu.
• Adding a wildcard symbol may retrieve word variants: so sanh y ((lang xa) or (lang van)) hoi. hieu van cam thuc dan thanh doi cua tu*.