Perhaps you should try some spelling variations:
thieu sach » thien hach, hieu cach, theo sach
chieu sach » chinh sach, chiet tach, chieu sang
thanh tran » thanh trang, thanh toan, thanh tra
tran tuan » tran xuan, tran quang, tran thanh
tuan dung » tuan duong, tran dung, tan dung
dung cong » dung trong
cong bai » cuong bai, cong hai, cung bai
bai toan » bai tap
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu sach) OR (chieu sach)) - thanh tran tuan dung cong bai toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) OR (chieu sach)) - thanh tran tuan dung cong bai toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) OR (chieu sach)) - thanh tran tuan dung cong bai toan cau*.