Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tinh doi » trinh doc, trinh do, tinh hoc
hoi lang » hoa lang, hoi dan
nam thuc » nam thuoc, am thuc, nam thu
thuc va » thuc vat, thuc dan, thuc day
cua tre » cuu tre, cua triet, dua tren
hieu ve » hieu va, hieu van
va tinh » may tinh
ve nam » he nam, va nam, le nam
o lang » hoa lang
cua te » cua tu

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) OR (hoi lang)) xa hoi. hieu ve nam thuc va tinh doi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((o lang) OR (hoi lang)) xa hoi. hieu ve nam thuc va tinh doi ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((o lang) OR (hoi lang)) xa hoi. hieu ve nam thuc va tinh doi ((cua tre) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: toc sach ((o lang) OR (hoi lang)) xa hoi. hieu ve nam thuc va tinh doi ((cua tre) or (cua te))*.