Basically I hear people complaining that you can't search the +skill/-skill legendaries for the desired skills. Here is my workaround the problem. (I am pretty sure someone else must have posted about it or maybe it's a well-known fact by now, but still many people are complaining, so I think I should share.)
First, search by armor, don't specify the specific armor plot, select legendaries only. In the prefix selection, put in the skill you want. If you want to search for SoJ, enter damage to elites. If you want to search for Mara or skullgrasp, put in int/dex/str of your choice. Click search, then sort by armor. If you enter damage to elites, Soj's should be on the first pages. If you sort by int/dex/str, mara's should be on the first pages, followed by skullgrasp. You can also swap the order of the prefix search so you can sort according to the first prefix you select.
Actually, after you search the first time, without a specific armor set, you can then switch to whatever specific gear piece and the affix should stay there until you change it. I've seen it work with sockets at least.
It's really stupid that it has to be done that way, but yeah.