Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach ty » sach y, sach tu, sach thu
ty sang » ty xang, ty hang, duy sang
sang ma » tang ma, nang ma, sang tao
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
ma hoi » mai hoi, xa hoi, ma hoa
va cam » va cham, va cac, va cao
xuc va » duc va, tuc va, luc va
cua te » cua tu
thiet » thieu

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 ty sang ma hoi. hieu va cam xuc va hanh vi ((cua te) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty sang ma hoi. hieu va cam xuc va hanh vi ((cua te) OR (va thiet))*.