Perhaps you should try some spelling variations:
tien thanh » tien thinh, tran thanh, den thanh
hien xanh » hien hanh, hien nhanh, chieu xanh
hanh tang » hanh trang, anh tang, hanh mang
cua thong » cua thuong, cua khong, cua tong
thong bai » thong tai, nhung bai, thong xay
tang cua » mang cua, hang cua, tang luan
bai toan » bai tap
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 ((hien xanh) or (tien thanh)) - hanh tang cua thong thong bai toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien xanh) OR (tien thanh)) - hanh tang cua thong thong bai toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((hien xanh) or (tien thanh)) - hanh tang cua thong thong bai toan cau*.