Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
thong cong » trong cong, thong thong, phong chong
doi chieu » doc hieu, ho chieu, mot chieu
tong cong » trong cong, cong cong, dung cong
trinh va » trinh van, trinh vat, trinh ve
tac phan » tac pham, tai phan, tac phat
doi chi » doi khi

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) or (doi chi)) sang - canh trinh va ((thong cong) OR (tong cong)) tac phan tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (doi chi)) sang - canh trinh va ((thong cong) OR (tong cong)) tac phan tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) or (doi chi)) sang - canh trinh va ((thong cong) OR (tong cong)) tac phan tu".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) or (doi chi)) sang - canh trinh va ((thong cong) OR (tong cong)) tac phan tu*.