Try this:

For a string in A1

B1: =IF(SUM(COUNTIF(A1,{"now *","* now","* now *"})),"Yes","No")

That formula behave correctly in the below situations:
PHRASE TO TEST RETURNED VALUE
the now look Yes
now is the time Yes
the time is now Yes
to know me No
it is known to me No
a nowhere man No

Does that help?
***********
Regards,
Ron

XL2002, WinXP


"vito" wrote:

i want to know whether a string is in a cell, built-in search function,
using formula of vlookup and find do not help.

e.g. i'm searching the word "now"

the text "i want to know whether a string is in a cell, built-in search
function, using formula of vlookup and find do not help." will be returned
as a match while it is not i want.

could anybody tell me what i can do? thanks in advance.