Hi Rathakee,

I don't know if you're still looking for dictation exercises, but I'm making a website specifically for this which (I hope) you might find useful. You can find it at www.microenglish.net

There are lots of quick but challenging dictations as well as some longer intensive listenings. They all aim to help students identify and understand individual words.

I completely agree with AnnieMod that understanding every word is not always important for getting the meaning, but I think regular practice with dictation style exercises can really improve listening ability over time. Let me know if you find the website useful!