Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nhan tai » hang tai, van tai, toan tai
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cac tuc » cac toc, cac tu, cac tac
han tai » hang tai, van tai, toan tai
cuc te » cua te, cuc thue, cuc tieu

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 nang ma hoa. hieu va cac tuc xa ((han tai) OR (nhan tai)) cuc te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang ma hoa. hieu va cac tuc xa ((han tai) OR (nhan tai)) cuc te".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang ma hoa. hieu va cac tuc xa ((han tai) OR (nhan tai)) cuc te*.