Perhaps you should try some spelling variations:
chat doc » chat hoc, chau doc, thuat doc
lai cua » dai cua, hai cua, thai cua
va hanh » van hanh, va thanh, va danh
va chat » van chat, va phat, cao chat
tu sach » thu sach, su sach, te sach
ky dang » ky nang, ky danh
ky sang » ky nang, ky tang, duy sang
hieu va » lieu va, hieu qua
ma hoi » mai hoi, xa hoi, ma hoa
doc va » duoc va, hoc va, duc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ky sang) or (ky dang)) ma hoi. hieu va chat doc va hanh ((lai cua) OR (lai chau)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky sang) OR (ky dang)) ma hoi. hieu va chat doc va hanh ((lai cua) OR (lai chau)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky sang) or (ky dang)) ma hoi. hieu va chat doc va hanh ((lai cua) OR (lai chau)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky sang) or (ky dang)) ma hoi. hieu va chat doc va hanh ((lai cua) OR (lai chau)) tre*.