Why physics (science) articles and journals differ pedagogically with books? During the undergraduate, students are introduced to new materials through reading books and lectures. They go through all the semester struggling with solving exercises of different levels. However, when they become new researchers, they face disturbance to familiarize themselves with the journals in concern, i.e., everybody agrees that the researcher should take enough background, even though, the traditional proceedings may not work to dive into a large topic of research that comes up with updates for almost every day. Particularly, reading such articles keeps it fuzzy from what's happening on the ground. In addition, lots of proofs (if we speak in terms of physics) are not clear if not missing. I wonder how this could be solved?
The textbooks that students use are written for novices. Scientific papers reporting research results are written for experts. And not just any experts but domain experts, or even sub-sub-sub-domain experts. So the current situation is probably about as good as it can be. Why?

Not everyone needs to be an expert in a field, but many people need some knowledge of it. So, in schools, students study the basics of things without any attempt to teach them everything. Students get a working knowledge of a lot of things which lets them be successful either in putting those ideas together to solve problems (application) or to go deeper and use further study to become experts (theory). 

But you note that the step from novice to expert is a big one. 

Think about closing the gap. Should we make school much much harder? Should we make scientists try to explain everything to novices whenever they write? Both of those would be steps backward, I think. The first would mean more failures, the second would slow down the march of science and make scientific papers repetitive so that the beauty of new results gets lost in the chaff. 

There are papers (and books) at the intersection, however. Some people prefer to write survey papers in a given field, attempting to bring the general understanding of a sub field more accessible to a general audience. Carl Sagan was good at that sort of thing in astronomy, for example. 

However, surveys of a field are only written fairly late, after the discoveries of a field have had time to settle in the minds of the experts, proving their worth. The most important discoveries can take quite a long time to become integrated into the general thinking of experts. Only then do the survey papers make much sense. 

But if a novice wants to become an expert it can be a long and hard journey. University education, especially graduate education, is supposed to put a student on a path to expertise. Working on research with an expert advisor is the most common way. But the first few (hundred) scientific papers will be difficult. It becomes easier with practice. But so does riding a bicycle.



Note: Even graduate level textbooks are written for novices, but in a sub-field rather than the overall field. My first look as measure theory was in grad school and, while I had a lot of mathematics experience, I was a novice in that particular subject.