Perhaps you should try some spelling variations:
quang luong » quang cuong, quang vuong, quang phuong
hoc thieu » toc thieu, hoc hien
trung can » trung cap, trung van, trong can
luong tai » dung tai, luong va
ho chieu » theo chieu, doi chieu, mot chieu
tung cai » tung mai, trung cap, trung cau
tai toan » bai toan, tap toan, tai tuan
toan cao » toan ban, toan tap

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: ((ho chieu) OR (hoc thieu)) xanh - thanh ((tung cai) OR (trung can)) quang luong tai toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (hoc thieu)) xanh - thanh ((tung cai) OR (trung can)) quang luong tai toan cao~".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (hoc thieu)) xanh - thanh ((tung cai) OR (trung can)) quang luong tai toan cao*.