<s>
In	O
text	B-Language
processing	I-Language
,	O
a	O
proximity	B-Application
search	I-Application
looks	O
for	O
documents	O
where	O
two	O
or	O
more	O
separately	O
matching	O
term	O
occurrences	O
are	O
within	O
a	O
specified	O
distance	O
,	O
where	O
distance	O
is	O
the	O
number	O
of	O
intermediate	O
words	O
or	O
characters	O
.	O
</s>
<s>
In	O
addition	O
to	O
proximity	O
,	O
some	O
implementations	O
may	O
also	O
impose	O
a	O
constraint	O
on	O
the	O
word	O
order	O
,	O
in	O
that	O
the	O
order	O
in	O
the	O
searched	O
text	O
must	O
be	O
identical	O
to	O
the	O
order	O
of	O
the	O
search	O
query	B-Library
.	O
</s>
<s>
By	O
limiting	O
search	B-Application
results	I-Application
to	O
only	O
include	O
matches	O
where	O
the	O
words	O
are	O
within	O
the	O
specified	O
maximum	O
proximity	O
,	O
or	O
distance	O
,	O
the	O
search	B-Application
results	I-Application
are	O
assumed	O
to	O
be	O
of	O
higher	O
relevance	O
than	O
the	O
matches	O
where	O
the	O
words	O
are	O
scattered	O
.	O
</s>
<s>
Commercial	O
internet	B-Application
search	I-Application
engines	I-Application
tend	O
to	O
produce	O
too	O
many	O
matches	O
(	O
known	O
as	O
recall	O
)	O
for	O
the	O
average	O
search	O
query	B-Library
.	O
</s>
<s>
As	O
an	O
added	O
benefit	O
,	O
proximity	O
searching	O
helps	O
combat	O
spamdexing	O
by	O
avoiding	O
webpages	O
which	O
contain	O
dictionary	O
lists	O
or	O
shotgun	O
lists	O
of	O
thousands	O
of	O
words	O
,	O
which	O
would	O
otherwise	O
rank	O
highly	O
if	O
the	O
search	B-Application
engine	I-Application
was	O
heavily	O
biased	O
toward	O
word	O
frequency	O
.	O
</s>
<s>
Note	O
that	O
a	O
proximity	B-Application
search	I-Application
can	O
designate	O
that	O
only	O
some	O
keywords	O
must	O
be	O
within	O
a	O
specified	O
distance	O
.	O
</s>
<s>
Proximity	O
searching	O
can	O
be	O
used	O
with	O
other	O
search	O
syntax	O
and/or	O
controls	O
to	O
allow	O
more	O
articulate	O
search	O
queries	B-Library
.	O
</s>
<s>
Sometimes	O
query	B-Library
operators	O
like	O
NEAR	O
,	O
NOT	O
NEAR	O
,	O
FOLLOWED	O
BY	O
,	O
NOT	O
FOLLOWED	O
BY	O
,	O
SENTENCE	O
or	O
FAR	O
are	O
used	O
to	O
indicate	O
a	O
proximity-search	O
limit	O
between	O
specified	O
keywords	O
:	O
for	O
example	O
,	O
"	O
brick	O
NEAR	O
house	O
"	O
.	O
</s>
<s>
In	O
regards	O
to	O
implicit/automatic	O
versus	O
explicit	O
proximity	B-Application
search	I-Application
,	O
as	O
of	O
November	O
2008	O
,	O
most	O
Internet	B-Application
search	I-Application
engines	I-Application
only	O
implement	O
an	O
implicit	O
proximity	B-Application
search	I-Application
functionality	O
.	O
</s>
<s>
That	O
is	O
,	O
they	O
automatically	O
rank	O
those	O
search	B-Application
results	I-Application
higher	O
where	O
the	O
user	O
keywords	O
have	O
a	O
good	O
"	O
overall	O
proximity	O
score	O
"	O
in	O
such	O
results	O
.	O
</s>
<s>
If	O
only	O
two	O
keywords	O
are	O
in	O
the	O
search	O
query	B-Library
,	O
this	O
has	O
no	O
difference	O
from	O
an	O
explicit	O
proximity	B-Application
search	I-Application
which	O
puts	O
a	O
NEAR	O
operator	O
between	O
the	O
two	O
keywords	O
.	O
</s>
<s>
However	O
,	O
if	O
three	O
or	O
more	O
than	O
three	O
keywords	O
are	O
present	O
,	O
it	O
is	O
often	O
important	O
for	O
the	O
user	O
to	O
specify	O
which	O
subsets	O
of	O
these	O
keywords	O
expect	O
a	O
proximity	O
in	O
search	B-Application
results	I-Application
.	O
</s>
<s>
Web	B-Application
search	I-Application
engines	I-Application
which	O
support	O
proximity	B-Application
search	I-Application
via	O
an	O
explicit	O
proximity	O
operator	O
in	O
their	O
query	B-Library
language	O
include	O
Walhello	B-Application
,	O
Exalead	B-Application
,	O
Yandex	O
,	O
Yahoo	O
!,	O
Altavista	O
,	O
and	O
Bing	B-Application
:	O
</s>
<s>
When	O
using	O
the	O
Walhello	B-Application
search-engine	B-Application
,	O
the	O
proximity	O
can	O
be	O
defined	O
by	O
the	O
number	O
of	O
characters	O
between	O
the	B-Application
keywords	I-Application
.	O
</s>
<s>
The	O
search	B-Application
engine	I-Application
Exalead	B-Application
allows	O
the	O
user	O
to	O
specify	O
the	O
required	O
proximity	O
,	O
as	O
the	O
maximum	O
number	O
of	O
words	O
between	O
keywords	O
.	O
</s>
<s>
Yahoo	B-Application
!	I-Application
</s>
<s>
Google	B-Application
Search	I-Application
supports	O
AROUND( #	O
)	O
.	O
</s>
<s>
Bing	B-Application
supports	O
NEAR	O
.	O
</s>
<s>
Ordered	O
search	O
within	O
the	B-Application
Google	I-Application
and	O
Yahoo	B-Application
!	I-Application
</s>
<s>
search	B-Application
engines	I-Application
is	O
possible	O
using	O
the	O
asterisk	O
( *	O
)	O
full-word	O
wildcards	B-Algorithm
:	O
in	O
Google	B-Application
this	O
matches	O
one	O
or	O
more	O
words	O
,	O
and	O
an	O
in	O
Yahoo	B-Application
!	I-Application
</s>
<s>
(	O
This	O
is	O
easily	O
verified	O
by	O
searching	O
for	O
the	O
following	O
phrase	O
in	O
both	O
Google	B-Application
and	O
Yahoo	B-Application
!	I-Application
</s>
