Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
va hanh » van hanh, va thanh, va danh
nang ro » nang co, nang ho, nang ra
cua tre » cua te, cuu tre, cua triet
ro hoi » co hoi, o hoi, mo hoi
su nam » sung nam
xuc va » duc va, tuc va, luc va
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: ((tu sach) or (thu sach)) ky nang ro hoi. hieu ((tu nam) OR (su nam)) xuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang ro hoi. hieu ((tu nam) OR (su nam)) xuc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang ro hoi. hieu ((tu nam) OR (su nam)) xuc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang ro hoi. hieu ((tu nam) OR (su nam)) xuc va hanh vi cua tre*.