Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
nam thuc » nam thuoc, am thuc, nam thu
thuc day » thuc dan, thuc vat
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
day dan » day danh, dao dan, cay dan
vai cua » hai cua, lai cua, bai cua
va nam » van nam, ha nam, va nay

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 (thuoc sach)) ky nang xa hoi. hieu va nam thuc day dan ((vai cua) OR (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) ky nang xa hoi. hieu va nam thuc day dan ((vai cua) OR (dai cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (thuoc sach)) ky nang xa hoi. hieu va nam thuc day dan ((vai cua) OR (dai cua)) tre*".