Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
chieu sang » chieu sach, chieu xanh, hieu lang
hiem ngan » kim ngan, viem gan
hanh tang » hanh trang, anh tang, hanh mang
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan tap » toan ban
tang va » trang va, tang van, thang va

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((hiem ngan) or (chieu sang)) - hanh tang va nhung cong tap toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hiem ngan) OR (chieu sang)) - hanh tang va nhung cong tap toan tap*.