Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
vat tinh » sat tinh, vat sinh, hoat tinh
tinh doi » trinh doc, trinh do, tinh hoc
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
cua tre » cuu tre, cua triet, dua tren
sach o » sach lo, sac o, sach y
o lang » hoa lang, hoi lang
ve nam » he nam, va nam, le nam
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 xa hoi. hieu ve nam thuc vat tinh doi ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach o lang xa hoi. hieu ve nam thuc vat tinh doi ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: toc sach o lang xa hoi. hieu ve nam thuc vat tinh doi ((cua tre) or (cua te))*.