Perhaps you should try some spelling variations:
dong khuong » dong huong, dong thuong, dong khung
trong chuan » thong chuan, trong chan, trong thuan
khuong tinh » chuong trinh, phuong trinh, phuong binh
hieu quang » thieu quang, hieu quan, hieu qua
trang chua » tranh chua, trang phuc, trang cho
hieu sang » chieu sang, hieu lang, nhieu tang
toan tap » toan ban

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((hieu sang) or (hieu quang)) - hanh ((trang chua) OR (trong chuan)) dong khuong tinh toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (hieu quang)) - hanh ((trang chua) OR (trong chuan)) dong khuong tinh toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) or (hieu quang)) - hanh ((trang chua) OR (trong chuan)) dong khuong tinh toan tap".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu quang)) - hanh ((trang chua) OR (trong chuan)) dong khuong tinh toan tap*.