Perhaps you should try some spelling variations:
thien thanh » tien thanh, thi thanh, hien hanh
thanh trung » thanh tung
trung thanh » truong thanh
thanh trong » tranh trong, hanh trong, nhanh trong
kien sach » dien sach, vien bach, kien mac
cong vang » cong lang, cong quang, cong ngang
cong van » cong san, song van, cong tan
tuan cap » than cap, thuan cam, toan cao

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 (thien thanh)) - thanh trung thanh trong ((cong van) OR (cong vang)) tuan cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((kien sach) OR (thien thanh)) - thanh trung thanh trong ((cong van) OR (cong vang)) tuan cap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((kien sach) or (thien thanh)) - thanh trung thanh trong ((cong van) OR (cong vang)) tuan cap".
• Adding a wildcard symbol may retrieve word variants: hoc ((kien sach) or (thien thanh)) - thanh trung thanh trong ((cong van) OR (cong vang)) tuan cap*.