Perhaps you should try some spelling variations:
thanh trung » thanh tung
trung tuan » trung thanh, trung tam, tran tuan
thong cong » trong cong, tong cong, thong thong
hien sach » dien sach, thien hach, chieu sach
kien sach » dien sach, vien bach, kien mac
hang cong » dang cong, hang nong, bang cong
bai toan » bai tap
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 (kien sach)) - thanh trung tuan ((thong cong) or (hang cong)) bai toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien sach) OR (kien sach)) - thanh trung tuan ((thong cong) OR (hang cong)) bai toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien sach) OR (kien sach)) - thanh trung tuan ((thong cong) or (hang cong)) bai toan tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien sach) OR (kien sach)) - thanh trung tuan ((thong cong) or (hang cong)) bai toan tap*.