Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
hieu va » hieu qua
cac tac » cac toc, cac bac, cac dac
va danh » va dinh, va dan, va hanh
danh ca » dan ca, doanh cua, danh cho
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
tac va » tac da, tac xa, tuc va
ca cua » co 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 y nang ((le hoi) or (ma hoa)). ((hieu va) or (lieu va)) cac tac va danh ca 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) OR (lieu va)) cac tac va danh ca cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((le hoi) or (ma hoa)). ((hieu va) or (lieu va)) cac tac va danh ca cua tre*.