Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
danh lai » danh sai, gianh lai, dinh lam
cau luc » cau truc, cau phuc
lai cua » dai cua, hai cua, lai chau
ky song » k song, ky cong, ky trong
song xa » song cua
hieu va » lieu va, hieu qua
cau duc » cao duc, chu duc, cau truc
va danh » va dinh, va dan, va hanh
cua te » cua tu

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) OR (cau luc)) va danh lai 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) OR (cau luc)) va danh lai 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) OR (cau luc)) va danh lai cua te".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky song xa hoi. hieu va ((cau duc) OR (cau luc)) va danh lai cua te*.