Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
doanh van » doan van, doanh va, doanh ban
cua nuoc » cua quoc, cua nguoi, cua thuoc
va doanh » van doanh, vay doanh, va danh
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
van cua » vang cua, ban cua, dan 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: ((thuoc sach) or (tu sach)) y lang xa hoi. hieu ve ((cua nuoc) or (hoc nuoc)) va doanh van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (tu sach)) y lang xa hoi. hieu ve ((cua nuoc) OR (hoc nuoc)) va doanh van cua tre.
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (tu sach)) y lang xa hoi. hieu ve ((cua nuoc) or (hoc nuoc)) va doanh van cua tre*.