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
nang xa » nang x, lang xa, nang ma
hieu ha » hieu hoa, hieu va, hieu ca
day dan » day danh, dao dan, bay dan
cay dan » cac dan, ca dan, cay lanh
vai cua » dai cua, hai cua, lai 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) or (thuoc sach)) ky nang xa hoi. hieu ha nam thuc ((day dan) OR (cay dan)) vai 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 ha nam thuc ((day dan) OR (cay dan)) vai 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 ha nam thuc ((day dan) OR (cay dan)) vai cua tre*".