Perhaps you should try some spelling variations:
chat doc » chat hoc, chau doc, thuat doc
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
su sach » so sach
va chat » van chat, va phat, cao chat
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
vu sach » vu bach, vu khach
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua

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

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