Hi,
in Italian, I understand from the context. In English, I just don't understand, LOL.
The more vocabulary you know, the less trouble you have reading. But learning vocabulary takes a lot of time, it takes years. First you learn basic words, like "metal". Then you go on learning other words, like "copper". The last step is learning words like "nitrogen". It takes a lot of time, yeah...
Some articles are easier to read than others. In some articles there are words that native speakers hardly ever use in any occasion. I might be mistaken, but I once cheked out the New York Times, and it seemed to me they used "weird English" (= I didn't understand a single word, lol). But as an example of something much better, I find that The Los Angeles Times uses a very good English.
So it depends what you read. Technical stuff is full of difficult words, but most of them come from Latin, so I can guess the meaning most times. The problem is the pronunciation and the stress are completely different, so I always have trouble remembering the correct pronunciation (which is one of my major problems).