First what draws my attention is that your regular URL is not as clean to start with. I would advise you to remove the spaces and change them for hyphens—if possible. URL are also case insensitive so there is actually no use for uppercase characters, but using them is personal preference though it makes them less readable and when rewriting it's an extra process to change them.
When rewriting a URL, you should think of your URL as parts. There is the domain which is divided in: subdomain (www), domain-name (tangailbazar) and the top-level domain (com). After the domain begins the cleaning up (you can also do a lot of rewriting on the domain, but in your case you will not).
To keep your rewrite process clear and simple (because URL rewriting with mod_rewrite can give massive headaches) you want every part of a rewritten URL (between slashes) to translate to a parameter in the raw URL. So in your case: ID=9014&show=Hot and Cool Water Filter
are two parameters that should be used in your clean URL. When rewriting the URL you would pick the value of key (parameter) ID
and show
and use them in your clean URL. In your case you need the ID parameter in the clean URL otherwise you can never not load your destination URL.
RewriteRule ^.+/(.+)/(.+)+$ adview_details.php?ID=$1&show=$2 [L]
This rule will change the request for:
www.tangailbazar.com/9014/Hot%20and%20Cool%20Water%20Filter
into:
www.tangailbazar.com/adview_details.php?ID=9014&show=Hot%20and%20Cool%20Water%20Filter
This is the best you can do in this case, otherwise you will have to change some things about the structure of the destination URL.
An important thing you need to get hold of is that the name URL rewriting is misleading, you actually don't rewrite anything, you translate the requested URL from the browser into the URL where you're page is located. So it's more of a 'URL translate' then a 'URL rewrite'. In creating user friendly URL's you most of the time are removing the parameter keys (show=) and file extension (.php) from the URL to make them more readable.
You will always need to use the dynamic parts in your URL and you can clean the static parts.
I hope this will help you solve your problem or at least make some things clear on rewriting URL's.
Good luck!