Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
dang xa » dang xay, lang xa, dang ha
thuc va » thuc vat, thuc dan, thuc day
dan thi » dang thi, tran thi, dinh thi
cuu tre » cua tre, cau tren, cau treo
cu tren » tu tren, dua tren
y dang » ky dang, 2 dang, _ dang
va dan » ca dan, va dao, va dau
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 y dang xa hoi. hieu van nam thuc va dan thi ((((cuu tre) or (cua te))) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y dang xa hoi. hieu van nam thuc va dan thi ((((cuu tre) OR (cua te))) OR (cu tren)).
• Adding a wildcard symbol may retrieve word variants: toc sach y dang xa hoi. hieu van nam thuc va dan thi ((((cuu tre) or (cua te))) or (cu tren))*.