Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hieu manh » chieu xanh, hieu nganh, dieu hanh
trinh qua » trinh quan, trinh cua, trinh quang
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
qua dung » quang dung, su dung, qua song
van toan » van tuan, van tan, van thanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu manh - hanh trinh qua dung cong ((xuan toan) or (van toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu manh - hanh trinh qua dung cong ((xuan toan) OR (van toan)) cao.
• Adding a wildcard symbol may retrieve word variants: hoc hieu manh - hanh trinh qua dung cong ((xuan toan) or (van toan)) cao*.