OT: How to force a Mac to search for network shares?

[Tiemo Hollmann TB]

Hello,

opening the finder (on lion) it takes pretty long until my Mac (Wifi
connected) finds all shares in my network, and after getting town to standby
it loses the shares.

Is there a way / shortcut to force the mac to search for network shares,
like F5 on windows or even to keep a share in the finder list?

Thanks

Tiemo