On the selected tags, click the highlighted icons as shown in the screenshot below so that they turn to a red exclamation mark:
The yellow star means that items are shown that may have the tag. If you select multiple tags and all of them are set to "*", all the items are shown that have any one of the tags (tag1 or tag2 or tag3, etc).
The red exclamation mark means that only items are shown that actually have the tag. If you select multiple tags and all of them are set to "!", only items are shown that have all of the tags (tag1 and tag2 and tag3, etc).
You may mix the modes, e.g., if you want to show only dresses, but that are either red or blue. In this case, you would only set the "dress" tag to "!"