Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hanh tang » hanh trang, anh tang, hanh mang
cua thong » cua thuong, cua khong, cua tong
cong bang » cuong bang, dong bang, hong bang
yen tinh » tuyen tinh
cong ban » cong san, cong tan, cong dan
toan cao » toan ban, toan tap
so yen » so yeu, o yen, su yen

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

• Performing a fuzzy search may retrieve terms with similar spellings: so yen tinh - ((hanh tang) or (hanh trinh)) cua thong ((cong ban) OR (cong bang)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so yen tinh - ((hanh tang) OR (hanh trinh)) cua thong ((cong ban) OR (cong bang)) toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so yen tinh - ((hanh tang) or (hanh trinh)) cua thong ((cong ban) OR (cong bang)) toan cao".
• Adding a wildcard symbol may retrieve word variants: so yen tinh - ((hanh tang) or (hanh trinh)) cua thong ((cong ban) OR (cong bang)) toan cao*.