Perhaps you should try some spelling variations:
hien nhanh » hien hanh, thien thanh, tien thanh
hien xanh » hien hanh, chieu xanh, hien khanh
thong tai » truong tai, thong tin, hang tai
hang cua » mang cua, huong cua, thong cua
tai toan » bai toan, tap toan, tai tuan
toan cau » toan cao, toan ban, toan tap
hang ca » hang va, nang cao, hang tai

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hien xanh) or (hien nhanh)) - hanh ((hang cua) OR (hang ca)) thong thong tai toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien xanh) OR (hien nhanh)) - hanh ((hang cua) OR (hang ca)) thong thong tai toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien xanh) or (hien nhanh)) - hanh ((hang cua) OR (hang ca)) thong thong tai toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien xanh) or (hien nhanh)) - hanh ((hang cua) OR (hang ca)) thong thong tai toan cau*.