Perhaps you should try some spelling variations:
khong thong » thong thong, thong thuong, phong chong
khong trong » khoang trong, thong trong, phong trong
hieu quang » thieu quang, hieu quan, hieu qua
sang than » cang thang, dang thanh, sang tao
hoc hieu » hoc thieu, hoc hien, doc hieu
anh dang » anh dung, anh bang, anh danh
anh dong » anh huong, anh son
than cao » toan cao, thai cao, than cap

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: hoc hieu quang - ((anh dang) OR (anh dong)) cua ((khong thong) OR (khong trong)) sang than cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu quang - ((anh dang) or (anh dong)) cua ((khong thong) OR (khong trong)) sang than cao~".
• Adding a wildcard symbol may retrieve word variants: hoc hieu quang - ((anh dang) or (anh dong)) cua ((khong thong) OR (khong trong)) sang than cao*.