Perhaps you should try some spelling variations:
hoc thuyet » hoc chuyen
hanh tranh » canh tranh, hanh trinh, hanh trang
cong quang » luong quang, thong quang, duong quang
quang toan » quang tuan, quang tran, quang doan
hoc thiet » hoc thieu, hoc hien, toc thieu
cua dung » cua dang, cua dong, cua rung
qua dung » quang dung, su dung, qua song
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: ((hoc thiet) or (hoc thuyet)) tach - hanh tranh ((cua dung) OR (qua dung)) cong quang toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thiet) OR (hoc thuyet)) tach - hanh tranh ((cua dung) OR (qua dung)) cong quang toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc thiet) or (hoc thuyet)) tach - hanh tranh ((cua dung) OR (qua dung)) cong quang toan cau".
• Adding a wildcard symbol may retrieve word variants: ((hoc thiet) or (hoc thuyet)) tach - hanh tranh ((cua dung) OR (qua dung)) cong quang toan cau*.