Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh tai » thanh tai, hang tai, han tai
tu sach » thu sach, su sach, tu cach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
xuc va » duc va, tuc va, luc va

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 (te sach))) or (toc sach)) ky nang xa hoi. hieu va cam xuc va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((tu sach) OR (te sach))) OR (toc sach)) ky nang xa hoi. hieu va cam xuc va hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((tu sach) OR (te sach))) or (toc sach)) ky nang xa hoi. hieu va cam xuc va hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((((tu sach) OR (te sach))) or (toc sach)) ky nang xa hoi. hieu va cam xuc va hanh tai cua tre*.