- Most of the papers I would find that way would be behind paywalls, and inaccessible to the people who asked me to find them
- I'd prefer to help those people know how they can check facts for themselves
If you read an article which makes claims, for example an article which claims that artificial sweeteners are terrible for your health, or an article which claims that all homeopathy is bunkum, the very first thing you should do is ask yourself is that really true? Always ask where is the evidence? If you just do that, instead of swallowing everything you read, you're already way ahead of the game.
How can you find out if something is really true? There are a variety of online resources you can use and ideally you should use a combination of them if you want to be really sure of something.
Wikipedia: You should never trust any single source of information and that definitely goes for Wikipedia. Wikipedia is a terrible place to stop looking for information but it can be a pretty good place to start. Wikipedia pages should always give references for any claims of fact, so check that there is a reference, then check out the reference to see if it really does say what the Wiki article claims it says, and whether you think it is a reliable source of information or not. Also check the edit history of the page to see if they thing you want to know about is in the middle of a furious revert war or something like that. If the last edit to this information was made a while ago and the sources seem to be sound and it's an actively edited page (where vandalism would be caught and reverted early) then you can have a fair bit of faith in the content.
Snopes: Snopes checks the veracity of urban myths like The Hook or The Microwaved Pet but it also debunks loads of food myths such as margarine is one molecule away from plastic or the dangers of aspartame. It's carefully researched and it gives sources. But remember, no one site is the last word in trustworthiness.
Google Scholar: This is a terrific and little-known resource where you can search scholarly literature from peer reviewed journals even if you are not a student or an academic. You can get many full text papers, and many more abstracts (a short summary of the full paper written by the author of the paper, not summarised by someone else). It works just like the google search engine we're all familiar with. Type in some keywords and get a bunch of results, then start reading.
Just plain old Google: But use with caution. Don't just see if you can find a website that contains the information you hoped to find. Think about what kind of a site it is on. If it is just some random blog (like this one) you can't necessarily trust the information on there. It might be reliable (like this one!!) or it might be a load of hooey. Keep looking until you find a credible source of information.