Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
cuc ban » cua ban, cuu ban, duc ban
cac ban » cac dan, cac van, can ban
cua tre » cuu tre, cua triet, dua tren
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ma hoa. hieu ve pham ((cuc ban) or (cac ban)) doanh tai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoa. hieu ve pham ((cuc ban) OR (cac ban)) doanh tai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ma hoa. hieu ve pham ((cuc ban) or (cac ban)) doanh tai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoa. hieu ve pham ((cuc ban) or (cac ban)) doanh tai ((cua tre) OR (cua te))*.