Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach thu » sach thue, sach thieu, sach tham
thu hang » thi hang, thuc hanh, thu huong
chat huu » pham huu
dieu cua » dieu tra
hang xa » hoang xa, hang va, hang ca
hieu va » lieu va
van anh » van thanh, van minh
cua tre » cua te, cuu tre, cua triet
tuan » quan, tran, luan

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

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