Perhaps you should try some spelling variations:
hanh trung » thanh trung, hanh trang, manh trung
trien cong » thien cong
hieu lang » chieu sang, hieu quang, nhieu tang
luan cong » luat cong, luong cong, luan chung
trong can » trong canh, trong chan, trong cac
doc hieu » toc thieu, hoc thieu, hoc hien
can ban » van ban, toan ban
ban thi » dan thi, tran thi, dang thi

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 lang - hanh trung ((luan cong) or (trien cong)) trong can ban thi~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - hanh trung ((luan cong) OR (trien cong)) trong can ban thi*.