It stalls the research on those items then it will set the remaining time to what it would be if you hadn't placed those points into the research boost. You already "lost" those items but the research Que is still there. As to the item order it will start again after you respec with the first item you started on, then I have been told that it moves on to the next item. I can't confirm this as I put the points back in to the trade skill before the first item was completed so then it began researching the second item from the point it was at when I respecced.
Current researches won't be cancelled, so you won't lose any items. But you will, of course, lose the time bonus unless you put skill points back to the research skill.