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, te sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cuu tre, cua triet, dua tren
va cam » va cham, va cac, va cao
xuc va » duc va, tuc va, luc va
cua te » cua tu

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