Most people I know use some online tool to search for Maven artifacts. But each has it's own shortcomings. There used to be several out there (jarvana, artifact-repository, mavenreposearch etc.), but nowadays are just two: http://mvnrepository.com/ (unofficial, yet often used) and http://search.maven.org/ (official). Btw. to be fair there are others like bintray.com or maven-repository.com, but they are niche, most people don't know about them and their search functionality is even worse. I just finished my own website with hopefully best search engine: http://javalibs.com
Well known libraries
org.apache.karaf.assemblies.features:spring (not even on the first couple of pages)
org.apache.karaf.jpa:hibernate (correct result was on third page)
Less known libraries
org.hibernate:hibernate-search-quickstart (no, but second result is correct even though it's deprecated module and the right module with artifactId hibernate-search-orm is number 11)
org.hibernate:hibernate-core (no, but number 9 is correct even though it's deprecated and the right module is number 15)
org.hibernate:hibernate-search-engine (no, but number 2 is correct one and number 3 is the deprecated module, which is also correct)
These tests show that:
search.maven.org search is based only on groupId and artifactId and for example if you match artifactId, it returns these results first even though it's some obscure library which nobody cares about.
mvnrepository.com search is based on groupId and artifactId, but it's ordered by "artifact popularity aka usages" (how many artifacts in Central repository use it). Mostly it returns relevant results, but when you look for some library and it contains a popular name, it's more popular sibling library will win.
javalibs.com is based on popularity search, but it's search is more intelligent. Moreover it has autocomplete, which nobody else has.