Perhaps you should try some spelling variations:
dong phuong » duong phuong, dung phuong, dong huong
phuong tinh » phuong trinh, phuong binh, khuong tinh
hieu sang » chieu sang, hieu lang, hieu quang
thang cua » thong cua, hang cua, than cua
trung cua » truong cua, trung tuan, trung cap
doc hieu » toc thieu, hoc thieu, hoc hien
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 - hanh ((thang cua) or (trung cua)) dong phuong tinh toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sang - hanh ((thang cua) OR (trung cua)) dong phuong tinh toan tap.
• Adding a wildcard symbol may retrieve word variants: doc hieu sang - hanh ((thang cua) or (trung cua)) dong phuong tinh toan tap*.