Perhaps you should try some spelling variations:
nhung duong » nhung dung, nhung huong, nhung tuong
duong manh » duong van
manh toan » thanh toan, anh tuan, tinh toan
ho chieu » theo chieu, hoc thieu, doi chieu
trinh va » trinh van, trinh vat, trinh vi
trinh ve » trinh he, trinh vi, trinh viet
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((theo tieu) or (ho chieu)) tinh - hanh ((trinh va) or (trinh ve)) nhung duong manh toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((theo tieu) OR (ho chieu)) tinh - hanh ((trinh va) OR (trinh ve)) nhung duong manh toan cau.
• Adding a wildcard symbol may retrieve word variants: ((theo tieu) or (ho chieu)) tinh - hanh ((trinh va) or (trinh ve)) nhung duong manh toan cau*.