Student or Learner
dear sir i want to know what is the best english dictionary for advance learner exemple in oxford dictionary contain more word than cambridge dictionary
There are online versions of both of these dictionaries. The one for Longman is The Longman Dictionary of Contemporary English, though I usually recommend the Longman Dictionary of American English.
I would go to both the Longman and Cambridge sites to see what they have.
There is a Cambridge Dictionary of American English as well.
Here are the links:
Longman English Dictionary Online
Longman English Dictionary Online - Widgets
Cambridge Dictionaries Online - Cambridge University Press
Cambridge Advanced Learner's Dictionary - Cambridge University Press