Perhaps you should try some spelling variations:
chieu sach » chiet tach, chieu sang, chieu xanh
canh trinh » canh tranh, hanh trinh, canh tinh
nhung cong » dung cong, thong cong, hang cong
trinh va » trinh van, trinh vat, trinh ve
cong tan » cong tac, cong san, cong thanh
tan phan » toan phan, than phan, van phan

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((chieu sach) or (chinh sach)) - canh trinh va nhung cong tan phan tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu sach) OR (chinh sach)) - canh trinh va nhung cong tan phan tu.
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sach) or (chinh sach)) - canh trinh va nhung cong tan phan tu*.