Perhaps you should try some spelling variations:
thanh trong » thanh trung, tranh trong, hanh trong
dong trong » duong trong, dung trong, cong trong
hien sach » dien sach, kien sach, thien hach
hien hanh » dieu hanh
trong van » trong cac
tap toan » tap quan, bai toan
tap doan » tap quan

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

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