Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, hieu cach
truong cao » truong dai
hoc thieu » toc thieu, hoc hien
truong ca » truong va, trong ca, truong dai
dung cong » dung trong
tap toan » tap doan, tap quan, bai toan
van tuan » van quan, van ban, anh tuan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu sach - thanh ((truong ca) OR (truong cao)) dung cong ((tap toan) OR (van tuan)) tap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu sach - thanh ((truong ca) OR (truong cao)) dung cong ((tap toan) or (van tuan)) tap~".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sach - thanh ((truong ca) OR (truong cao)) dung cong ((tap toan) or (van tuan)) tap*.