There's no need to put a comma between your search terms or to use capitalization. Searching for "yogurt chicken tomatoes" might lead to a tasty recipe for roast chicken with paprika and yogurt sauce.
You can also add cooking related terms or styles of cuisine to find recipes that match your mood, dietary restrictions, or cooking equipment. Try "Indian chicken yogurt tomatoes" or "wok chicken yogurt tomatoes" for different results.
You won't always land on a page with a recipe. Sometimes you'll find pages that are actually links to several different recipes with some of the ingredients you've listed. It's still a good starting point for finding that perfect recipe.
Cookin' With Google can be found on the Research Buzz website.