Also -- try limiting your search by domain (.edu, .gov, .org, etc.) by typing site:.edu in the box along with your search terms.
Google Advanced Search
This video describes the features of Google Advanced Search, which can help you focus your search results on exactly what you need.
Keep in Mind
You are more likely to find academic sources on .gov and .edu sites, but you still need to look at the purpose and other factors. Many .edu sites host student blogs, personal pages, news, etc. Not all pages with a .edu or .gov ending are academic, but they are good starting places for research. To limit to these sites, add site:gov or site:edu to the end of your search in Google or another search engine (note that there are no spaces).
.org sites may have some academic works, but again will require evaluation. Many nonprofits will publish research as reports or fact sheets. Note that many nonprofit organizations may have sponsors or a certain mission. Be sure that you are aware of this (look for a Mission or About Us page on their site). A specific mission may mean that there is bias in the information an organization is promoting.
Examine the tone and purpose of the site. Ideally, resources for college level research papers should be written to inform, educate, and/or share research. Some organizations may be trying to sell a product or persuade others of their point of view, which could affect the information they choose to present or highlight. Some organizations might also have a political stance that can affect their presentation of research. Even if a biased site supports your thesis, it lacks credibility and weakens your argument.