Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
hanh trang » thanh trung, canh tranh, hanh trinh
va phuong » va thuong, cac phuong
thong dan » thong van, tuong dan, thong den
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap
va cong » tai cong, cua cong

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)) - hanh trang ((va cong) or (va phuong)) thong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu khang)) - hanh trang ((va cong) OR (va phuong)) thong dan toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) OR (thieu khang)) - hanh trang ((va cong) or (va phuong)) thong dan toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) OR (thieu khang)) - hanh trang ((va cong) or (va phuong)) thong dan toan cao*.