Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cua viet » ca viet, hoa viet, cua vat
tang xa » trang xa, tang ma, lang xa
va cham » va chat, va tham
dan sai » danh sai, doan sai, dan tai
y tang » ky tang, 6 tang, 7 tang
va cam » va cac, va cao, va cai
va dan » ca dan, va dao, va dau
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y tang xa hoi. hieu ((va cam) OR (va cham)) duc va dan sai ((cua viet) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y tang xa hoi. hieu ((va cam) OR (va cham)) duc va dan sai ((cua viet) OR (cua tu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y tang xa hoi. hieu ((va cam) OR (va cham)) duc va dan sai ((cua viet) or (cua tu))".
• Adding a wildcard symbol may retrieve word variants: toc sach y tang xa hoi. hieu ((va cam) OR (va cham)) duc va dan sai ((cua viet) or (cua tu))*.