Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
toc hieu » toc thieu, doc hieu, hoc thieu
dang van » hoang van, hang va
dan dung » van dung, tin dung, ap dung
dong dat » dong vat, dong ha, dong tai
dung dat » dung va, dung tai
van dan » van ban, ban dan, van dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc hieu lang - dang van dan dung ((dong dat) or (dung dat)) phan tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc hieu lang - dang van dan dung ((dong dat) OR (dung dat)) phan tu.
• Adding a wildcard symbol may retrieve word variants: toc hieu lang - dang van dan dung ((dong dat) or (dung dat)) phan tu*.