Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, hieu cach
hoc thieu » toc thieu, hoc hien
trung cua » truong cua, trung tuan, trung cap
tran tuan » tran xuan, tran quang, tran thanh
dung cong » dung trong
tang van » dang van, hoang van, trong van
tan van » tran van, luan van, dang van

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 - hanh ((trung cua) OR (tran tuan)) dung cong ((tan van) OR (tang van)) ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu sach - hanh ((trung cua) or (tran tuan)) dung cong ((tan van) OR (tang van)) ban~".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sach - hanh ((trung cua) or (tran tuan)) dung cong ((tan van) OR (tang van)) ban*.