Q. I am searching for articles concerning Autism and Communication.

You did not mention what databases you have tried so I am going to start with our OneSearch database. Remember, I do not know your thesis and what you are thinking about so I'm constructing a "best guess" type of search. Inside OneSearch, I went to the advanced search screen. Type autism in one box and communication in another box. In both cases, click the dropdown menu and click on "Subject." In the third text box, type relationship and click the dropdown menu and select "Abstract." This search yields about 370 titles. If you limit by date (for example, between 2007 and 2012), your results shrink to 172. From there, you will need to evaluate the relevancy of the article to your research to see if any of them fit.

To explain the search, I wanted "autism" and "communication" to be specific subject headings. Also, I wanted the word "relationship" to be included in the abstract. The dropdown menus act as limiters. As you evaluate your results, keep in mind that this is not a perfect strategy. This is normal for high-end research. There are multiple options and choices of terms that will change the result list. Some other suggestions include:

• Paying attention to the terms used in the title, abstract, and subject heading fields in article citations. You may see some additional terms that perhaps you haven't considered yet. You may want to add them to a larger search or start a new search with the new terms. Be a "word detective" and pay attention for clues to new terms to use. 
• Using the dropdown options when available. These will vary by database but if you have more options, you can add more complexity to your searching. If you select nothing, you will be searching by global keyword which means the search engine will examine every field (including full-text) in your results. In other words, your search terms may, indeed, appear in the article but the article itself may not necessarily be about autism or communication.
• If you see an article of interest but do not see a full-text option, click the LinkSource link. It will cross-check our other databases. Follow upt to see if the article is available elsewhere. If so, it should display at the top. If not, click the Interlibrary Loan option and we will try to get the article for you as quckly as possible.

If you can get your results as close as you can to 300 (give or take 50), that's pretty good (anything larger will take even more time to sort out) but you will have to determine the overall relevancy. Don't be surprised if you have to tweak the search again and try additional terms.

I hope this begins to point you in the right direction. If not, please let us know.