Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
hanh tranh » canh tranh, hanh trinh, hanh trang
nhung cong » dung cong, thong cong, nhung don
hien sach » dien sach, kien sach, chieu sach
tranh cua » doanh cua, manh cua
hang cong » dang cong, hang nong, bang cong
tap toan » tap doan, tap quan, bai toan
toan tap » toan ban

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 (thien hach)) - hanh tranh cua ((nhung cong) or (hang cong)) tap toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien sach) OR (thien hach)) - hanh tranh cua ((nhung cong) OR (hang cong)) tap toan tap.
• Adding a wildcard symbol may retrieve word variants: hoc ((hien sach) or (thien hach)) - hanh tranh cua ((nhung cong) or (hang cong)) tap toan tap*.