Perhaps you should try some spelling variations:
trinh trung » trinh truong, trinh trong, sinh trung
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
trung con » trung son, trung co, trang con
dung cong » dung trong
con dung » con duong, cong dung, con rung
cong dan » cong san, cong tan, huong dan
dan van » dang van, doan van, dao van

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sang) or (hieu lang)) - trinh trung con dung cong dan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sang) OR (hieu lang)) - trinh trung con dung cong dan van ban.
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sang) or (hieu lang)) - trinh trung con dung cong dan van ban*.