Perhaps you should try some spelling variations:
truong cong » trong cong, truong dong, truong long
hieu tinh » chieu tinh, lieu tinh, kieu tinh
trinh han » trinh quan
doc hieu » toc thieu, hoc thieu, hoc hien
trinh tu » trinh ky, trinh do
cong dan » cong san, cong tan, huong dan
dan phan » doan phan, dan chan, van phan

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: doc hieu tinh - hanh ((trinh tu) OR (trinh han)) truong cong dan phan tu~.
• Adding a wildcard symbol may retrieve word variants: doc hieu tinh - hanh ((trinh tu) or (trinh han)) truong cong dan phan tu*.