Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
tu sach » thu sach, su sach, te sach
dao bai » cao bai, dao hai, dap bai
dao lai » dao lam, dao hai, dao li
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, dang xay, lang van
o lang » hoa lang, hoi lang

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: ((tu sach) OR (toc sach)) o lang xa hoi. hieu va cac nuoc va ((dao lai) OR (dao bai)) cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (toc sach)) o lang xa hoi. hieu va cac nuoc va ((dao lai) OR (dao bai)) cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) o lang xa hoi. hieu va cac nuoc va ((dao lai) OR (dao bai)) cua tre*.