Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
sang trong » lang trong, mang trong, nang trong
hieu lang » chieu sang, hieu quang, nhieu tang
tinh quan » tinh quang, trinh quan, tin quan
trong can » trong canh, trong chan, trong cac
quan lua » quan luan, quan cua, quang cua
lua sang » luc sang, bua sang, cua sang
can van » cac van, can ban, tan 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 sach)) - tinh quan lua sang trong can van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu lang) OR (chieu sach)) - tinh quan lua sang trong can van ban.
• Adding a wildcard symbol may retrieve word variants: doc ((hieu lang) or (chieu sach)) - tinh quan lua sang trong can van ban*.