Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nham thu » nham thuc, nam thu, pham thu
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
va nham » va cham, va tham, va nha
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
di cua » doi cua, de cua, do cua

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 xa hoi. lieu va nham thu ((va danh) OR (va hanh)) ((di cua) or (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. lieu va nham thu ((va danh) OR (va hanh)) ((di cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang xa hoi. lieu va nham thu ((va danh) OR (va hanh)) ((di cua) or (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. lieu va nham thu ((va danh) OR (va hanh)) ((di cua) or (dai cua)) tre*.