Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, diep quang
hanh trinh » canh tranh, hanh chinh
vat dung » van dung, viet dung, mat duong
cong van » cong vang, cong san, song van
van toan » van tuan, van tan, van thanh
toan cau » toan cao, toan ban, toan tap
va dung » van dung, va duong, va ung

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 quang) or (hieu qua)) - hanh trinh ((va dung) OR (vat dung)) cong van toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu quang) OR (hieu qua)) - hanh trinh ((va dung) OR (vat dung)) cong van toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu quang) or (hieu qua)) - hanh trinh ((va dung) OR (vat dung)) cong van toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu quang) or (hieu qua)) - hanh trinh ((va dung) OR (vat dung)) cong van toan cau*.