Do tulips bloom once and thereafter only the greenpart shows up?

It's complicated.

Tulips are perennials ... in the right climate. They will survive several years without replanting.

In adverse climates (the Netherlands is strongly associated with tulips, but the climate is not at all ideal for them), tulips are effectively annuals and are replanted every year.

Tulip bulbs do tend to get "spent" and need to be dug up, dried, and replanted every few years, though, even in climates they like. If this isn't done, they may just produce leaves rather than flowers. If you've had tulips that have bloomed before but are no longer doing so, this may revitalize the flowers.

Many state universities have an agricultural extension office that can provide you with guidelines for your area, or at least direct you to someone who can help. If you're lucky enough to live near a college with a botanical garden, you could try asking them; they're often happy to share their knowledge.