Perhaps you should try some spelling variations:
hien nhanh » hien hanh, thien thanh, tien thanh
hien xanh » hien hanh, chieu xanh, hien khanh
thong bai » thong tai, nhung bai, thong xay
hang cua » mang cua, huong cua, thong cua
bai toan » bai tap
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 bai 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 bai toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((hien xanh) or (hien nhanh)) - hanh ((hang cua) or (hang ca)) thong thong bai toan cau*.