Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
dau nuoc » dat nuoc, dau ngoc, cap nuoc
dan thai » dang thai, dan thi, dan than
thai cuu » thai cua, tai cuc, thi cuc
tu sach » thu sach, su sach, te sach
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
van dau » van dao, phan dau
cuu tre » cua tre, cau tren, cau treo
va dan » ca dan, va dao, va dau

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) or (toc sach)) ky lang xa hoi. hieu van dau nuoc va dan thai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) ky lang xa hoi. hieu van dau nuoc va dan thai cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky lang xa hoi. hieu van dau nuoc va dan thai cuu tre*.