Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
tu sach » su sach, te sach, tu cach
cac duc » cac du, cac dac, cac nuoc
cao duc » dao duc, cao suc, giao duc
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua
x hoi » xa hoi, o hoi, x ho

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 (thu sach)) ky nang x hoi. lieu va ((cac duc) or (cao duc)) van hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang x hoi. lieu va ((cac duc) OR (cao duc)) van hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) ky nang x hoi. lieu va ((cac duc) or (cao duc)) van hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) ky nang x hoi. lieu va ((cac duc) or (cao duc)) van hanh va cua tre*.