Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
doi chieu » doc hieu, doi chi, ho chieu
trinh vin » trinh van, trinh tin, trinh ven
dung cong » dung trong
trinh vi » trinh va, trinh ve, trinh viet
cong van » cong vang, cong san, song van
van toan » van tuan, van tan, van thanh
toan cao » toan ban, toan tap

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doi chieu sach - canh ((trinh vi) OR (trinh vin)) dung cong van toan cao~.
• Adding a wildcard symbol may retrieve word variants: doi chieu sach - canh ((trinh vi) or (trinh vin)) dung cong van toan cao*.