@feiyang lu I see you are using a local host setup to call Bing API. I am not sure how this is setup to call the actual Bing search API but to limit the responses to a certain domain or website, you will have to use the site operator in your query parameter. Here is an example of your request.
As you can see, the site operator uses the following pattern:
"query text":site="site1","site2"
You should also ensure your query does not have an intermediate ":" since that might be causing to read the text after ":" as an operator instead. Please see the reference for full details on how to use the operators with query parameter. I hope this helps!!
If this answers your query, do click Accept Answer
and Yes
for was this answer helpful. And, if you have any further query do let us know.