Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
hien xanh » hien hanh, hien nhanh, chieu xanh
chau tinh » cuu tinh, ha tinh, cua tinh
dung cong » dung trong
trinh va » trinh van, trinh vat, trinh ve
tap toan » tap doan, tap quan
bai toan » bai tap
va dung » van dung, va duong, vat dung

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hien xanh) or (chau tinh)) - canh trinh va dung cong ((tap toan) OR (bai toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien xanh) OR (chau tinh)) - canh trinh va dung cong ((tap toan) OR (bai toan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien xanh) or (chau tinh)) - canh trinh va dung cong ((tap toan) OR (bai toan)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien xanh) or (chau tinh)) - canh trinh va dung cong ((tap toan) OR (bai toan)) cao*.