Perhaps you should try some spelling variations:
cong thinh » cong trinh, cong thanh, cong tinh
thinh dan » thinh doan, trinh dan, hinh dan
doc hieu » hoc thieu, hoc hien
tinh dan » trinh dan, tinh da, binh dan
dan thuc » dan toc, am thuc
thuc dan » thuc hanh, hoc dan, thuc vat
dan cong » dang cong, van cong, dan dong

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc hieu) or (toc thieu)) sang - tinh dan thuc dan cong thinh dan ca~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (toc thieu)) sang - tinh dan thuc dan cong thinh dan ca*.