The search engine features both full-text search of gallery titles, as well as filtering by tags.
Tags are of the form prefix:tag — for example, tag:vanilla or artist:NaPaTa. Tags are case-insensitive.
If your search is for a single tag, you can simply enter the tag's suffix into the search bar, and the search engine will automatically search for that tag. So, for example, a search for NaPaTa is the same as a search for artist:NaPaTa.
However, if your search includes multiple tags, you must enter in the prefix before both tags. So a search for napata vanilla won't work. You need to search for artist:NaPaTa tag:vanilla instead.
If your tag name includes spaces, put quotes around the suffix. For example, magazine:"Comic Kairakuten 2019-04"
You can exclude tags from your searches by prefixing them with a minus sign. For example, you can search -tag:vanilla to exclude all items that feature that tag.
You can also perform rather complicated searches. For example, if you search tag:ahegao The -tag:x-ray Real tag:kogal Izumi-san, the search engine will perform a search for galleries that feature the tags tag:ahegao tag:kogal, that do not have the tag tag:x-ray, plus match a full-text search for The Real Izumi-san, which will get you this gallery.
If you're a registered user, you can also permanantly hide tags by going to the User Settings page in the user menu up in the navbar. You can also set tags you want to watch, and all galleries featuring those tags will be highlighted in all of your result pages.