Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
nhanh mang » nhanh lang, nhanh quang, nhanh thang
hanh mang » hanh trang, nhanh lang, thanh hang
trong san » trong cac, cong san, dong san
doc hieu » toc thieu, hoc thieu, hoc hien
toan cau » toan cao, toan ban, toan tai
toan tap » toan ban

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu quang - ((hanh mang) OR (nhanh mang)) ung dung trong san ((toan cau) OR (toan tap))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu quang - ((hanh mang) or (nhanh mang)) ung dung trong san ((toan cau) OR (toan tap))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu quang - ((hanh mang) or (nhanh mang)) ung dung trong san ((toan cau) OR (toan tap))*.