Someone above mentioned Janet Lansbury. One of the things she puts forward as a "mantra for parents" is acknowledge feelings. Also, let feelings be!
If you know that your daughter is upset & frustrated at not getting her way, find ways to speak to her that acknowledge this. Her impulse to hit or otherwise "act out" those feelings makes sense; what she needs is support for the emotional experience she's having so that she can begin developing the capacity to manage/tolerate the feelings better. Verbalizing her displeasure instead of hitting/throwing would be better/more mature (though frequently parents have a hard time with the words & tones children use to express their upset feelings, too!) This is how you get there!
I wouldn't resort to punishment to try to "discourage" hitting when you realize that it is happening for a reason. With punishment (or with ignoring) you are not teaching her anything about WHAT to do when she's frustrated or angry (which is something she'll feel again, and again.) Instead, work on limiting the behavior (or, ideally, preventing it) with a calmly warm physical limit that keeps both of you safe, and acknowledge her feelings.
This acknowledgment can be as simple as, "You didn't like that."
Saying something like "I know, you weren't happy with me" or "I know, you wanted the scissors & I took them away" while you prevent her hands from hitting is the idea. Even simply, "I know."
If she becomes upset and cries or screams at this point, simply listen to her feelings. Stay with her while she's upset and ride it out. You don't have to "name" feelings; you can just be there. Or say, "I know it's hard."
Her feelings do make sense. Feeling powerless because you're unable to make things go your way is a VERY uncomfortable sensation; it's often what parents are feeling when we get upset during conflicts with our kids, or get pulled into power struggles! Recognize that it makes sense for her to want to FORCE you to go her way, or it makes sense to have a hard time handling a strong feeling gracefully, and just show her (via your presence & attitude) that she is still "okay" and acceptable as far as you are concerned, and that strong feelings are part of human experience. This is how she begins to gain more tolerance for these feelings & to develop the ability to regulate her emotions.
Angry words (verbalizing the feelings) are more mature than hitting or other physical acting out. They are not always socially acceptable or easy to hear, but when that is the case you can offer guidance with a response that (again) acknowledges the feelings expressed and at the same time, models more mature ways of expressing the exact same feelings. Simply respond to her angry words with acknowledgment of how upset she is, or how unhappy she is with your decision/action. There is no need to "correct" the language or tone in the moment if you can focus on the message being communicated, and then reflect it back in more acceptable language. This, too, is the process by which children learn to express those (same) feelings less primitively, in increasingly socially-acceptable and respectful ways as they develop emotional maturity. This is the way maturation happens.
I usually put my focus on my own internal regulation (or lack) because often, I feel agitated when my child is upset. As soon as I put my attention on that & really notice the degree to which I'm agitated in reaction to my child's upset feelings or behavior, I'm better able to "allow feelings" rather than resisting them and feeling upset. Instead of feeling like I need to make it stop, I'm able to see it for what it is & take care of things.
Make sure you're not modeling the same thing the child is doing--getting all upset when you don't like what is happening and you want someone to behave differently! (And looking for some way to make them change.)