Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thu sach » tu sach, thuat sach, thuoc sach
kho tang » cao tang
phat huy » phan huy, pham huy, pham huu
thanh va » thanh van, hanh va, thanh ha
tang ma » mang may, tang van
hieu va » lieu va, hieu qua
huy gia » quy gia, huyen gia, thue gia
su tien » su kien, su hien, tu tieng

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((te sach) or (toc sach))) or (thu sach)) kho tang ma hoa. hieu va phat huy gia thanh va su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((te sach) OR (toc sach))) OR (thu sach)) kho tang ma hoa. hieu va phat huy gia thanh va su tien.
• Adding a wildcard symbol may retrieve word variants: ((((te sach) or (toc sach))) or (thu sach)) kho tang ma hoa. hieu va phat huy gia thanh va su tien*.