Perhaps you should try some spelling variations:
lang trong » dung trong, cong trong, dong trong
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
quang lua » quang cua, quang tuan, quang xuan
trong tan » trong quan, trong cac, trong ca
lua lang » cua lang, dua lang, lua sang
tran van » luan van

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) or (chieu sang)) - tinh quang lua lang trong tan tran van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu lang) OR (chieu sang)) - tinh quang lua lang trong tan tran van.
• Adding a wildcard symbol may retrieve word variants: doc ((hieu lang) or (chieu sang)) - tinh quang lua lang trong tan tran van*.