Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
hieu ve » hieu van
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua

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

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