Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
ky song » k song, ky cong, ky trong
song xa » song cua
hieu va » lieu va, hieu qua
cau duc » cao duc, cau luc, chu duc
va danh » va dinh, va dan, va hanh
lai cua » hai cua, lai chau, thai cua
va cau » van cau, va cac, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ky song xa hoi. hieu va cau duc va danh ((lai cua) OR (dai cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky song xa hoi. hieu va cau duc va danh ((lai cua) OR (dai cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky song xa hoi. hieu va cau duc va danh ((lai cua) OR (dai cua)) te".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky song xa hoi. hieu va cau duc va danh ((lai cua) OR (dai cua)) te*.