Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
dan thanh » dang thanh, danh thanh, ban thanh
thuc dan » thuc hanh, hoc dan, thuc vat
cam thuc » am thuc, nam thuc, cam thu
tay lang » tai lang, tay tang, tay quang
hieu van » hieu va, thien van, lieu va
co sach » bo sach, cuon sach, hoc sach
doi cua » dai cua, hoi cua
van cam » van nam, van lam, van cau
so sanh » do sanh
y lang » o lang, _ lang, yen lang
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: ((co sach) or (so sanh)) ((y lang) OR (tay lang)) xa hoi. hieu van cam thuc dan thanh doi cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((co sach) OR (so sanh)) ((y lang) OR (tay lang)) xa hoi. hieu van cam thuc dan thanh doi cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((co sach) or (so sanh)) ((y lang) OR (tay lang)) xa hoi. hieu van cam thuc dan thanh doi cua tu".
• Adding a wildcard symbol may retrieve word variants: ((co sach) or (so sanh)) ((y lang) OR (tay lang)) xa hoi. hieu van cam thuc dan thanh doi cua tu*.