When you buy resources from neighbor do you take the card or just get access to the resources you need?
No, you do not take the card. The neighbor retains the card; you are simply allowed to use your neighbor's cards, for a fee of course.
You can also buy the resource from the top corner of the civilization cards as well. It doesn't need to be a "card".
Just the resources.
The rules on page 4 define things pretty well.
Cards are called "structures", the brown ones can generate "resources"
Often, a player will want to build a structure requiring resources he or she does not produce.
If these resources are produced by a neighboring city – players sitting directly to the left or right of that player – the player will be able to purchase the missing resource(s) through commerce.
In red, there is a notice:
Important : the resources are not spent during construction. They can be used each turn, for the entire game. The production of a city is never reduced (the cards played are never discarded).
Obviously if you were to take the card, the production of the city would be reduced and this is prohibited.