Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tang van » dang van, hoang van, trong van
hieu cao » chieu cao, hieu cac, hieu ca
thuc van » thuc vat, thuc dan, thuc va
van hoi » van hoa, van hoc, van hoe
tuc van » truc van, tuc va, duc van
tuan ve » quan ve, luan ve, toan ve
cua tre » cua te, cuu tre, cua triet
y tang » ky tang, 6 tang, 7 tang

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 y tang van hoi. hieu cao chat ((tuc van) or (thuc van)) ((tuan ve) OR (tuan le)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y tang van hoi. hieu cao chat ((tuc van) OR (thuc van)) ((tuan ve) OR (tuan le)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y tang van hoi. hieu cao chat ((tuc van) or (thuc van)) ((tuan ve) OR (tuan le)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y tang van hoi. hieu cao chat ((tuc van) or (thuc van)) ((tuan ve) OR (tuan le)) cua tre*.