Perhaps you should try some spelling variations:
trong quang » truong quang, thong quang, trong quan
luong quang » luong quan, dung quang
chiet tach » chieu sach
thong cong » trong cong, tong cong, thong thong
doi chiet » doi chieu, doi chi, doi viet
cong san » cong tac
khan cap » than cap, khoan cam, phan cac
khan ap » han ap, khan dam

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi chiet tach - hanh ((trong quang) or (luong quang)) thong cong san ((khan cap) OR (khan ap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi chiet tach - hanh ((trong quang) OR (luong quang)) thong cong san ((khan cap) OR (khan ap)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi chiet tach - hanh ((trong quang) or (luong quang)) thong cong san ((khan cap) OR (khan ap))".
• Adding a wildcard symbol may retrieve word variants: doi chiet tach - hanh ((trong quang) or (luong quang)) thong cong san ((khan cap) OR (khan ap))*.