Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
dien cuc » dien tu, dieu cua, vien cac
cham hoc » cham soc, chat hoc, cham hoi
qua cham » qua hai, qua cac, va cham
nang xa » nang x, lang xa, nang ma
va nang » van nang, da nang, cam nang
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
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) or (thuoc sach)) va nang xa hoi. hieu qua cham hoc ((va danh) OR (va hanh)) dien cuc te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) va nang xa hoi. hieu qua cham hoc ((va danh) OR (va hanh)) dien cuc te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (thuoc sach)) va nang xa hoi. hieu qua cham hoc ((va danh) OR (va hanh)) dien cuc te".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (thuoc sach)) va nang xa hoi. hieu qua cham hoc ((va danh) OR (va hanh)) dien cuc te*.