Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang cho » nang chon, ngang cho, nang cao
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cho hoc » co hoc, khoa hoc
hieu ve » hieu va, hieu van
cac cau » cac mau, bac cau, ca cau
cau ban » can ban, cac ban, cuu ban
hanh di » hanh vi, hanh de, danh di
hang di » hang doi, hang vi, hang dien
ve cac » va cac, vien cac

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 nang cho hoc. hieu ve cac cau ban ((hanh di) or (hang di)) cua cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang cho hoc. hieu ve cac cau ban ((hanh di) OR (hang di)) cua cac*.