Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
cac tuc » cac toc, cac tu, cac tac
hang vi » hanh vi, hang di, khang voi
cua tre » cua te, cuu tre, cua triet
y nang » ly nang, v nang, may nang
ve cac » va cac, vien cac
tuc va » thuc va, truc va, tuc xa

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) OR (ky nang)) ma hoa. hieu ve cac tuc va ((hang vi) or (hang va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (ky nang)) ma hoa. hieu ve cac tuc va ((hang vi) OR (hang va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) OR (ky nang)) ma hoa. hieu ve cac tuc va ((hang vi) or (hang va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) OR (ky nang)) ma hoa. hieu ve cac tuc va ((hang vi) or (hang va)) cua tre*.