Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
doc hieu » toc thieu, hoc thieu, hoc hien
phan dau » phan tu, hang dau
gian dan » gian lang
dan dung » van dung, tin dung, ap dung
dung dat » dung va, dung tai
dat van » dao van, dat va, dam van
van phi » van chi, van phu, van nhi

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