Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thanh va » thanh van, hanh va, thanh ha
su triet » su viet, su tien, ve triet
cua viet » ca viet, hoa viet, cua vat
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
duc ban » duc tan, dua ban, duc man
duc van » duc va, duc tan, duc manh

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 ky lang xa hoi. hieu va cac ((duc ban) or (duc van)) thanh va ((su triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang xa hoi. hieu va cac ((duc ban) OR (duc van)) thanh va ((su triet) OR (cua viet)).
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang xa hoi. hieu va cac ((duc ban) or (duc van)) thanh va ((su triet) or (cua viet))*.