Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cac nuoc » cap nuoc, dat nuoc, cua nuoc
danh vai » danh va, doanh van, dang van
danh sai » dung sai, danh bat, danh dau
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
y lang » o lang, _ lang, tay lang

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y lang xa hoi. hieu ve ((cac nuoc) or (hoc nuoc)) va ((danh vai) OR (danh sai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y lang xa hoi. hieu ve ((cac nuoc) OR (hoc nuoc)) va ((danh vai) OR (danh sai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y lang xa hoi. hieu ve ((cac nuoc) or (hoc nuoc)) va ((danh vai) OR (danh sai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach y lang xa hoi. hieu ve ((cac nuoc) or (hoc nuoc)) va ((danh vai) OR (danh sai)) cua tre*.