Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
cac tuc » cac tu, cac tac, cac nuoc
cac toc » cac toi, cac nuoc, cac thoi
va danh » va dinh, va dan, va hanh
cho cua » co cua, chi cua, cho ca
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang

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 y nang ((le hoi) or (ma hoa)). hieu va ((cac tuc) or (cac toc)) va danh cho cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((le hoi) OR (ma hoa)). hieu va ((cac tuc) OR (cac toc)) va danh cho cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((le hoi) or (ma hoa)). hieu va ((cac tuc) or (cac toc)) va danh cho cua tre*.