Brown the chopped onion in butter in a large pan. Cut the salmon into small pieces and cook lightly. Pour on the vodka and leave to evaporate. Now add the fresh cream and bring to the boil. Season with salt and pepper. Cook the pasta in plenty of boiling, salted water. Drain quickly, retaining a little of the cooking water. Sauté the pasta in a pan with the sauce and blend well. Sauté the artichokes with oil and garlic and arrange on a plate as a bed for the pasta. Serve hot. Sprinkle with fresh, chopped herbs to taste.