Perhaps you should try some spelling variations:
thanh trong » thanh trung, hanh trong, nhanh trong
tranh trong » tran trong, trinh trong, anh trong
kien sach » vien bach, kien mac, viet sach
dien sach » dien anh
dong cong » duong cong, dung cong, dang cong
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than cao » toan cao, thai cao, than cap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((kien sach) or (dien sach)) - ((thanh trong) OR (tranh trong)) van dong cong dan than cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((kien sach) OR (dien sach)) - ((thanh trong) OR (tranh trong)) van dong cong dan than cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((kien sach) or (dien sach)) - ((thanh trong) OR (tranh trong)) van dong cong dan than cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((kien sach) or (dien sach)) - ((thanh trong) OR (tranh trong)) van dong cong dan than cao*.