Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
day nang » da nang, may nang, dai nang
day hang » dat hang, dai hang, dai thang
nam thuc » nam thuoc, am thuc, nam thu
nang xa » nang x, lang xa, nang ma
hiem he » hiem xe, hieu he, thien he
bo sach » co sach, hoc sach
cuu tre » cua tre, cau tren, cau treo
he nam » ha nam, nghe nam
di cuu » di cau, di cua, dinh cuu

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) or (bo sach)) ky nang xa hoi. hiem he nam thuc ((day hang) OR (day nang)) di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (bo sach)) ky nang xa hoi. hiem he nam thuc ((day hang) OR (day nang)) di cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (bo sach)) ky nang xa hoi. hiem he nam thuc ((day hang) OR (day nang)) di cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (bo sach)) ky nang xa hoi. hiem he nam thuc ((day hang) OR (day nang)) di cuu tre*.