I have a digital camera canon 350d for closer shots which lense would you buy?

If you mean close focusing of objects like, say, a picture of a coin on a table that you want to fill the frame you need a macro lens. These enable you to zoom in and focus closely. Written on the lens is the closest focusing distance it can achieve as well as the ratio it can reproduce.

For example, written on the lens maybe a ration of 1:2 which means it can focus down to an image and produce half the size as it is in real life, 1:1 means the object will be exactly the same size as in real life. (So when you put the coin on the photo it should fit over the picture perfectly), then 2:1 means the image is twice as big as in real life which means you can get all the detail in.

You can also use extension tubes or bellows with your normal lenses to help achieve the same effect only cheaper! But it does alter your aperture readings.

when I have a question about lenses
I go to adorama.com

If by closer shots you mean how do I take a shot of some mountains and make them look closer to me, or how can I take a photo of an animal and make it look larger in the photo, then you will need a telephoto lens. For your camera, this would begin at about 45 mm and the larger the number, the higher the magnification.

These are available both as zooms and prime (single focal length) lenses. If you haven't used one of them, I think you'll be amazed at what they can do!

My suggestion would be to try a few of them in a camera store, to determine how much magnification you want (and can afford!).