Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thuc dan » thuc hanh, hoc dan, thuc vat
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc day
cua tre » cua te, cuu tre, cua triet
va nam » van nam, ha nam, va nay
dan va » doan va, dan ca, ban va
va cua » va chua, via cua, ca cua

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 ky lang xa hoi. hieu va nam ((thuc va) OR (thuc dan)) dan va cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky lang xa hoi. hieu va nam ((thuc va) OR (thuc dan)) dan va cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. hieu va nam ((thuc va) OR (thuc dan)) dan va cua tre*.