Perhaps you should try some spelling variations:
cham duc » pham duc, cham soc, pham duy
van tuan » van quan, van ban, anh tuan
so sach » so sanh, bo sach, co sach
cua tre » cua te, cua triet, dua tren
tuan va » toan va, luan va, quan va
duc van » duc va, duc tan, duc manh
tu cham » toc cham, thi cham
sach ty » sach y, sach tu, sach thu
hieu tu » chieu tu, hieu tuc, hien tu
hoa hoi » khoa hoi, hoa doi, hoc hoi
ty dong » tay dong, tu dong, ly dong
cuu tre » cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty dong ((hoa hoi) or (hoa hoc)). hieu tu cham duc van tuan va ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty dong ((hoa hoi) OR (hoa hoc)). hieu tu cham duc van tuan va ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty dong ((hoa hoi) or (hoa hoc)). hieu tu cham duc van tuan va ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: so sach ty dong ((hoa hoi) or (hoa hoc)). hieu tu cham duc van tuan va ((cua tre) OR (cuu tre))*.