Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cau duc » cao duc, cau luc, chu duc
cua tre » cua te, cua triet, dua tren
anh kem » hanh kem, anh kiem, banh kem
van anh » van thanh, tuan anh, van minh
duc van » duc va, duc tan, duc manh
cuu tre » cau tren, cau treo
hieu ve » hieu va, hieu van
nang o » nang co, nang ho, nang ro
y nang » ky nang, ly nang, v nang
ve cau » ke cau, va cau, ve cac
o hoc » co hoc, mo hoc, so hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) y nang o hoc. hieu ve cau duc van anh kem ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y nang o hoc. hieu ve cau duc van anh kem ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y nang o hoc. hieu ve cau duc van anh kem ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y nang o hoc. hieu ve cau duc van anh kem ((cua tre) or (cuu tre))*.