Perhaps you should try some spelling variations:
phuong tuong » phuong duong, phuong luong, phuong trong
phong tuong » phong trong, thong thuong, thong thong
chieu tinh » trieu tinh, lieu tinh, chau tinh
hanh trinh » canh tranh, hanh chinh
tieu xanh » tieu danh, chieu xanh, dieu hanh
trinh va » trinh van, trinh vat, trinh ve
tac toan » tap toan, tam toan, hach toan
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: theo ((tieu xanh) OR (chieu tinh)) - hanh trinh va ((phuong tuong) OR (phong tuong)) tac toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((tieu xanh) or (chieu tinh)) - hanh trinh va ((phuong tuong) OR (phong tuong)) tac toan cao~".
• Adding a wildcard symbol may retrieve word variants: theo ((tieu xanh) or (chieu tinh)) - hanh trinh va ((phuong tuong) OR (phong tuong)) tac toan cao*.