Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
hanh dieu » han dieu, hinh dieu, hoang dieu
sach thu » sach thieu, sach tham, cach thuc
van hanh » van thanh, ban hanh, van anh
dieu tra » dieu tri, kiem tra, dieu cua
hang xa » hoang xa, hang va, hang ca
va chat » van chat, va phat, hoa chat
tra tre » tran tren, tran tri, tran tro

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach thu) OR (sach thue)) hang xa hoi. hieu ((va chat) or (cao chat)) va van hanh dieu tra tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach thu) OR (sach thue)) hang xa hoi. hieu ((va chat) OR (cao chat)) va van hanh dieu tra tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach thu) OR (sach thue)) hang xa hoi. hieu ((va chat) or (cao chat)) va van hanh dieu tra tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach thu) OR (sach thue)) hang xa hoi. hieu ((va chat) or (cao chat)) va van hanh dieu tra tre*.