Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
thuoc van » thuoc va, thuc van, thuoc ban
dang xay » dang van, van xay
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu le » hieu ve, hieu he, hieu ly
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
le nam » ly nam, he nam, le na
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: tu sach ky ((nang xa) or (dang xay)) hoi. hieu le nam thuoc van hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (dang xay)) hoi. hieu le nam thuoc van hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (dang xay)) hoi. hieu le nam thuoc van hanh va cua tre*.