I use Racket which comes with a ton of features that let me build larger systems. Other more pure Scheme systems like Guile also have the capabilities to build modules/libraries, etc... and there is a decent amount of code out there to do stuff. You do have less of a choice for certain things than languages like Perl or Python, but most modern Schemes or Scheme-like languages are pretty good.

Like every other language in the world?

Most large-ish Scheme systems have a module system. You're a bit limited if you stick with straight R5RS, but even then every serious compiler/interpreter has additional features. Not unlike Python, Perl, Ruby, PHP, etc. There is also R6RS and R7RS now, which have additional features now.