Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
duc van » duc va, duc manh, duc phan
cua tre » cua te, cuu tre, cua triet
va coc » va cuoc, va cac, va hoc
vi cua » vai cua, di cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (thuoc sach)) ky nang xa hoi. hieu va coc ((duc van) OR (duc tan)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) ky nang xa hoi. hieu va coc ((duc van) OR (duc tan)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thuoc sach)) ky nang xa hoi. hieu va coc ((duc van) OR (duc tan)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuoc sach)) ky nang xa hoi. hieu va coc ((duc van) OR (duc tan)) hanh vi cua tre*.