Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
nhung cong » dung cong, thong cong, hang cong
cong hach » cong sach, cong thanh, cong khanh
hach toan » thanh toan, manh toan
trang va » hang va
tran van » luan van
toan cao » toan ban, toan 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 sang) or (thieu khang)) - thanh ((trang va) OR (tran van)) nhung cong hach toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu khang)) - thanh ((trang va) OR (tran van)) nhung cong hach toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) or (thieu khang)) - thanh ((trang va) OR (tran van)) nhung cong hach toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (thieu khang)) - thanh ((trang va) OR (tran van)) nhung cong hach toan cao*.