Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu tinh » chieu tinh, lieu tinh, kieu tinh
trung cua » truong cua, trung tuan, trung cap
cua trong » cua truong, cua trung, qua trong
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
chon cac » cho cac, thong cac, chon loc
hoc cac » hoc cao

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 - thanh trung cua trong cong dan ((chon cac) OR (hoc cac))~.
• Adding a wildcard symbol may retrieve word variants: doc hieu tinh - thanh trung cua trong cong dan ((chon cac) or (hoc cac))*.