Depending on the scope and topic of your literature review, you might need to include information from resources beyond peer reviewed journals.
The guide below has many links to helpful government, NGO, international sites & resources beyond databases:
Evbestie. (2017, March 7) Filter Bubble Graphic. Wikimedia Commons https://commons.wikimedia.org/wiki/File:FilterBubble.jpg
Google tailors your search results based on your previous search history. It also makes assumptions based on your IP address. While this can make life easier, the danger is that you will only see one side to something.
Consider at least glancing at the 2nd and 3rd pages of your search results to see what Google might not think was as important to someone with your browser history & IP address, but might give you a more complete context to the research question.
Try using a Search Engine which does not provide results based on who you are: