While it is not always possible to refine a search to the point where only items interest turn up in the results, if -- like the OP -- you find yourself wading through pages of items that have nothing to do with what you are looking for, such as gundam figures when you are searching for WWII military models, then there are likely things you can do to refine your search further to eliminate the unwanted results.
To a certain extent you are limited by the categories and filter options that eBay provides. You are also limited by the details that the seller includes in the listing. If you are looking for a particular doll made in a particular year, but the seller fails to include any date information in the listing, then you may have difficulty finding that listing without going through lots of others as well.
You may know how to search, but many users search in different ways and some rely on specific techniques exclusively and ignore others that might be more effective. If users are reliant on browsing categories, then the category reorganization that eBay is undergoing can make things much harder.
Often users are quite certain that it is impossible to limit searches without using the old categories that eBay has removed. In some cases, such as involving classic car parts, there are very few ways to identify such items in a general way. But for many items in the trains and models categories, there are item-specifics that, if included by the seller when creating the listing, can be found using keywords or filters. So it is still possible to search for and find only N-scale train models, even though there is no longer a specific category just for that scale.
While many users are justifiably upset at the results of the changes that eBay has made, some are actually quite thankful when a search technique suggestion works to make a frequently-used search much more effective.
