Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va thanh » gia thanh, ban thanh, va tinh
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
qua cac » cua cac
cac tuc » cac toc, cac tu, cac tac
va hanh » van hanh, va danh, ban hanh

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 dang xa hoi. hieu qua cac tuc ((va hanh) OR (va thanh)) ((dai cua) or (tri cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang xa hoi. hieu qua cac tuc ((va hanh) OR (va thanh)) ((dai cua) OR (tri cua)) te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang xa hoi. hieu qua cac tuc ((va hanh) OR (va thanh)) ((dai cua) or (tri cua)) te*".