Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hoc thieu » toc thieu, hoc hien
trinh vat » trinh van, trinh luat, sinh vat
dung cong » dung trong
vat dung » van dung, va dung, viet dung
ban toan » ban than, van toan, bao toan
bai toan » bai 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 thieu) or (doi khi)) xanh - hanh trinh vat dung cong ((ban toan) OR (bai toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thieu) OR (doi khi)) xanh - hanh trinh vat dung cong ((ban toan) OR (bai toan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc thieu) or (doi khi)) xanh - hanh trinh vat dung cong ((ban toan) OR (bai toan)) cau".
• Adding a wildcard symbol may retrieve word variants: ((hoc thieu) or (doi khi)) xanh - hanh trinh vat dung cong ((ban toan) OR (bai toan)) cau*.