Whenever I pick up an item that says something like "+7.5 Starship Emitters, +7.5 Starship Deflectors, +11 Starship Sensors" I have no idea what it means. I know that certain space skills are affected by these things, but it's hard to figure out which of these stats I should focus on. Is there a handy chart or list somewhere?
Probably the best thing to do would be to open your skill window, select your science officer's skills from the drop-down menu in the upper right corner, and see which Starship Operations skills get highlighted. That will directly tell you what deflector stats you want.
But if you want to use the wiki, I'd start here and check out the different Science abilities. However, some of this information may be both incomplete and out of date. I had started to compile a list with the wiki info and the STO character builder, but I don't fully trust the accuracy of either source...
Each system is a skill you drop points into and has some clues when you click on them in the skill up screen. Using the drop down menu (in the upper right) of the the skill up screen will highlight the relevant skills, but it only lists the powers you have.