Perhaps you should try some spelling variations:
day thanh » dao thanh, dat thanh, dam thanh
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
da thanh » dao thanh, dat thanh, dam thanh
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet

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