Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
sach o » sach lo, sac o, sach y
o lang » hoa lang, hoi lang
ve nam » he nam, va nam, le nam

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 o lang xa hoi. hieu ve nam thuc ((va tinh) OR (may tinh)) doi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach o lang xa hoi. hieu ve nam thuc ((va tinh) OR (may tinh)) doi cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach o lang xa hoi. hieu ve nam thuc ((va tinh) OR (may tinh)) doi cua tre*.