There are academic, industrial and government or private institution researchers. For example, at some academic institutions, professors may be differentiated as either "teaching professors" or "research professors".
In general, every country has its own large national research centers with different research and development (R&D) profiles. They employ numerous researchers.
Researchers work not for students but for well defined short-term, middle-term and long-term R&D or RTD (Research and Technology Development) projects defined in the frame of the strategy of their organizations.
There are numerous necessary specializations of researchers, but in large research business institutions, interdisciplinary profiles of researchers are always more frequently requested. They have to adapt to new objectives and to cope with before unknown for them, systems, equipments and problems. Therefore, one of their important tasks is to cooperate with academic researchers and professors.
For the above reasons, the positions and the research work conditions of researchers in research or technological laboratories are different than in academic institutions.
The positions of researchers in large research centers/institutes have many specific names, but usually they are divided on three basic levels equivalent to: junior researcher, researcher, senior researcher.
The research activity is organized according to the specific company structure. Usually every researcher works in so called matrix structure, he/she is a member of a laboratory or other specialized unit, and in parallel temporally participates in one of more projects.
Many important scientific results of the industrial and military researchers' work are not published because they have either confidential or secret character. At a consequence, many valid scientists became slowly a “property” of companies.