Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dai hang » dai thang, dai han, dat hang
day hang » dat hang, day nang, dai thang
nam thuc » nam thuoc, am thuc, nam thu
hieu he » hieu ve, hiem he, hieu le
nang xa » nang x, lang xa, nang ma
so sach » so sanh, bo sach, co sach
doi cuu » doi cua, doi cuoc
cuu tre » cua tre, cau tren, cau treo
he nam » ha nam, nghe nam

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