Perhaps you should try some spelling variations:
thieu quang » hieu quang, thien quan, trien quang
dung phuong » dung thuong, bang phuong, dung chung
thieu sang » chieu sang, thieu khang, hieu lang
phuong dan » phuong danh, phuong doan, huong dan
trang cua » tranh cua, trung cua, thang cua
tang cua » mang cua, hang cua, tang luan
dan toan » van toan, dan than, manh toan
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 quang)) - hanh ((trang cua) or (tang cua)) dung phuong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu quang)) - hanh ((trang cua) OR (tang cua)) dung phuong dan toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) OR (thieu quang)) - hanh ((trang cua) or (tang cua)) dung phuong dan toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) OR (thieu quang)) - hanh ((trang cua) or (tang cua)) dung phuong dan toan cao*.