Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
dung cong » dung trong
hinh cua » chinh cua, tinh cua, dinh cua
sinh cua » manh cua, dinh cuu
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap
sinh va » sinh vat, tinh va, dinh van

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 - hanh ((hinh cua) or (((sinh cua) OR (sinh va)))) dung cong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - hanh ((hinh cua) OR (((sinh cua) OR (sinh va)))) dung cong dan toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien xanh - hanh ((hinh cua) or (((sinh cua) OR (sinh va)))) dung cong dan toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - hanh ((hinh cua) or (((sinh cua) OR (sinh va)))) dung cong dan toan cao*.