Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
tong cong » trong cong, cong cong, dung cong
van thanh » ban thanh
ho chieu » theo chieu, hoc thieu, doi chieu
doc hieu » toc thieu, hoc thieu, hoc hien
trinh va » trinh van, trinh vat, trinh ve
van tuan » van quan, van ban, anh tuan
va tong » va thong, va tuong, va trong

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: ((ho chieu) OR (doc hieu)) xanh - canh trinh va tong cong ((van thanh) OR (van tuan)) dat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (doc hieu)) xanh - canh trinh va tong cong ((van thanh) OR (van tuan)) dat~".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (doc hieu)) xanh - canh trinh va tong cong ((van thanh) OR (van tuan)) dat*.