Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
manh tuong » manh tung, minh tuong, anh huong
manh cuong » anh huong, manh hung, tang cuong
nhung cong » dung cong, thong cong, hang cong
hoc hieu » hoc thieu, hoc hien, doc hieu
tac toan » tap toan, hach toan, tich toan
tam toan » tap toan, tam than, pham toan

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu quang - ((manh tuong) OR (manh cuong)) va nhung cong ((tac toan) or (tam toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu quang - ((manh tuong) OR (manh cuong)) va nhung cong ((tac toan) OR (tam toan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu quang - ((manh tuong) OR (manh cuong)) va nhung cong ((tac toan) or (tam toan)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc hieu quang - ((manh tuong) OR (manh cuong)) va nhung cong ((tac toan) or (tam toan)) cao*.