Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
dang xay » dang van, van xay
cua tre » cua triet, dua tren, cua thep
dan tai » van tai, dan thi, han tai
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
cuu tre » cau tren, cau treo
va nam » van nam, ha nam, va nay
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.

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