Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
thang cong » thanh cong, thang long, thong cong
trong thoi » trong thi, trong tho, trong trot
doi chieu » doc hieu, doi chi, mot chieu
trong van » trong cac
tan trong » tran trong, toan trong, than trong
song van » hoang van, duong van, dang van
cong tan » cong tac, cong san, cong thanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi chieu sach - thanh ((song van) or (trong van)) thang cong tan trong thoi~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi chieu sach - thanh ((song van) OR (trong van)) thang cong tan trong thoi*.