EBSCO Guide (Cinahl, ASP, Business Source Complete...): Combine Searches

From Advanced Search, you can choose between AND or OR from the left side of the search bar
In the same search block, you only need to select one of the options. You can always combine your searches from Recent activity.

From Recent activity you can combine multiple search strings.
Select the keywords or search strings you want to combine and choose whether you want to combine with AND or with OR
Be aware that the most recent search will be automatically transferred to the search field, so REMEMBER to clear (Clear all) the search field if you are not going to use the previous search.

You can combine your free text words with the corresponding controlled keywords in the same search string.
Once you have your free text words, you can then search on the controlled keywords and click Add to search.

Change to OR between blocks. Click on Search, and you can see your combination of free text words and controlled keywords.

Normally, NOT should be used with caution as you risk excluding relevant results. However, it may be necessary if you need to limit the results.