Combining Boolean Terms
You can use more than one Boolean connector in a search and mix together different Boolean connectors in the same search.
Thus you could type:
impeachment AND richard pre/2 nixon
That would retrieve only stories in which the word impeachment appeared along with any of the variations on Richard Nixon's name.
Or if you were searching for protests or demonstrations against abortion, you could type:
abortion AND protest OR demonstration
That would retrieve any story that had both the word abortion and the word protest, or any stories that had both the word abortion and the word demonstration.