Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
cac nuoc » cap nuoc, dat nuoc, cua nuoc
danh vai » danh sai, danh va, doanh van
tu sach » su sach, te sach, tu cach
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
va danh » va dinh, va dan, va hanh
vai cua » dai cua, hai cua, lai cua
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) OR (tu sach)) y lang xa hoi. hieu ve ((cac nuoc) or (hoc nuoc)) va danh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) y lang xa hoi. hieu ve ((cac nuoc) OR (hoc nuoc)) va danh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (tu sach)) y lang xa hoi. hieu ve ((cac nuoc) or (hoc nuoc)) va danh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (tu sach)) y lang xa hoi. hieu ve ((cac nuoc) or (hoc nuoc)) va danh vai cua tre*.