Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, hieu manh
tong tuong » trong tuong, tuong tuong, tong thuong
trinh cua » tinh cua, trinh luat, trinh quan
tuong dan » huong dan, tung dan, xuong dan
sinh cua » manh cua, dinh cuu, sinh va
dan toan » van toan, dan than, manh toan
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 ((hieu nganh) or (thi thanh)) - hanh ((sinh cua) or (trinh cua)) tong tuong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu nganh) OR (thi thanh)) - hanh ((sinh cua) OR (trinh cua)) tong tuong dan toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu nganh) or (thi thanh)) - hanh ((sinh cua) or (trinh cua)) tong tuong dan toan cau*.