You can narrow your search by enclosing a phrase or group of words with quotation marks.
"systematic review" - Searches for the times when these two words are next to each other in this exact order.
systematic review [without quotation marks] - searches for these two word, regardless of if they happen to appear together or not. You may get an article in your list of results which is a book review about systematic interviewing.
gay OR LGBT
This search will find research that includes either
the term gay or the term LGBT. Using the
connector OR will give you more.
It works well for including similar terms.
PTSD AND military
This search will find research that only includes
both the term PTSD and the term military. Using
the connector AND will give you fewer results than OR.
adoption NOT bill
This search will find research that includes
the word adoption but won't include any of
that research that also includes the term bill.
That way if an article mentions a bill being
adopted that article wouldn't be included.
Truncation means you include a special character at the end of your search term which will broaden your search to include any word that starts with that group of letters.
flavor* = Finds not only the word flavor but also flavored, flavorful, flavoring, etc.
child* = Finds the word child, along with childhood, children, etc.
Using a Wildcard in your search means you can insert a symbol anywhere in a search term not just at the end, like the example above.
wom?n = Finds both women and woman
It is easy to follow reference citations from an article to get older research on the same or similar topics. Some databases also allow you to see which articles have cited an article forward. For example you may have found an excellent article in the database Social Services Abstracts from the year 1992. If other articles since then have studied this same article and cited it in their own papers, Citation databases such as Scopus and also Social Services Abstracts database will include a link to these articles so you can follow the research forward to find more current research on this same topic.