Perhaps you should try some spelling variations:
hien nhanh » hien hanh, thien thanh, tien thanh
cong khanh » cong thanh, cong khan, cong nhan
hien xanh » hien hanh, chieu xanh, hien khanh
hanh sinh » hanh tinh, hanh dinh, hinh sinh
cong hach » cong sach, cong thanh, trong hach
sinh qua » sinh quan, sinh cua, tinh quan
qua dung » quang dung, su dung, qua song
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 (hien nhanh)) - hanh sinh qua dung ((cong hach) OR (cong khanh)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien xanh) OR (hien nhanh)) - hanh sinh qua dung ((cong hach) OR (cong khanh)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien xanh) or (hien nhanh)) - hanh sinh qua dung ((cong hach) OR (cong khanh)) toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien xanh) or (hien nhanh)) - hanh sinh qua dung ((cong hach) OR (cong khanh)) toan cau*.