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
hieu va » lieu va, hieu qua
cam duc » cam xuc, cao duc, pham duc
dau sai » dau hai, dau tai, danh sai
cua tuc » cua duc, cua tu, cua thuoc
y tang » ky tang, 6 tang, 7 tang
va cam » va cham, va cac, va cao
va dau » va dao

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 duc va dau sai ((cua viet) or (cua tuc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y tang xa hoi. hieu va cam duc va dau sai ((cua viet) OR (cua tuc)).
• Adding a wildcard symbol may retrieve word variants: toc sach y tang xa hoi. hieu va cam duc va dau sai ((cua viet) or (cua tuc))*.