Perhaps you should try some spelling variations:
hoc thuyet » hoc chuyen
hanh trinh » canh tranh, hanh chinh
hoc thiet » hoc thieu, hoc hien, toc thieu
bang cong » dang cong, bang song, hang cong
dung cong » dung trong
manh toan » thanh toan, anh tuan, tinh toan
trinh va » trinh van, trinh vat, trinh ve
toan cau » toan cao, toan ban, toan tap

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

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