Perhaps you should try some spelling variations:
tong thuong » thong thuong, trong thuong, cong thuong
hieu nganh » vien nganh, hiem ngan, hieu manh
thuong dan » huong dan, thuong han, thuong dam
trinh cua » trinh luat, trinh quan, trinh luan
tinh cua » sinh cua, tinh chat, tranh cua
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 ((dieu hanh) or (hieu nganh)) - hanh ((trinh cua) OR (tinh cua)) tong thuong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((dieu hanh) OR (hieu nganh)) - hanh ((trinh cua) OR (tinh cua)) tong thuong dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((dieu hanh) or (hieu nganh)) - hanh ((trinh cua) OR (tinh cua)) tong thuong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((dieu hanh) or (hieu nganh)) - hanh ((trinh cua) OR (tinh cua)) tong thuong dan toan cau*.