Perhaps you should try some spelling variations:
lang trong » dung trong, cong trong, dong trong
hieu lang » chieu sang, hieu quang, nhieu tang
trong dan » trong dang, trong san, trong tan
toc hieu » toc thieu, doc hieu, hoc thieu
dan dung » van dung, tin dung, ap dung
vung dat » vung va
dung dat » dung va, dung tai

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 - lang trong dan dung ((vung dat) or (dung dat)) phan tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc hieu lang - lang trong dan dung ((vung dat) OR (dung dat)) phan tu.
• Adding a wildcard symbol may retrieve word variants: toc hieu lang - lang trong dan dung ((vung dat) or (dung dat)) phan tu*.