If you come up with zero results:
If you find a good article/book, look through the description to see if you can find better terms to use in your search, or look for other things by the same author(s).
Phrases - to search for a phrase or multiple word concept, use quote marks around the words - e.g., "climate change"
Truncation - use * near the end of a word to specify you want it to search for multiple endings for a word - e.g., climat* - will find climate, climates, climatic.
Be careful where you truncate as you could end up with unintended words - e.g, clim* will find climb in addition to the above words.
Combining concepts (a.k.a. Boolean Operators):
AND - requires EACH word to be in the results - e.g., cats and dogs and training
OR - will find ANY of the word(s) in the results - e.g., cat or cats
NOT - will find results that do NOT include the word(s) - e.g, Idaho crops not potato
You can also do fairly complex combinations using parentheses:
(cat or cats) and "house train*"
- this will bring back results that contain the phrases house training or house train and EITHER cat or cats. If you truncate cat* you would get way too many irrelevant results including catatonic, catalyst, etc.
In some databases, the connectors need to be in UPPERCASE while in others they do not.
In Google searches:
use + before a word to indicate it MUST appear in the results
use - before a word to indicate it must NOT appear in the results
Google ASSUMES you want an AND in between words unless you specify otherwise.