At last, it established a central concept indexing model theory.

In these different stages of phonological theory, markedness concept has played different role and exerted different power.

The core concept and the conceptual system are the bedrocks of a theory as well as the key factors of a theoretical opinion or a theoretical system,which in turn determine the power of its explanation.

It introduced the theory of unpleasant symptoms from aspects of background and development,core concept,influencing factors,internal and external evaluations,and theoretical application of the theory of unpleasant symptoms theory.

In the different historical period the key conception of the library science has different variations, the knowledge is the key conception of the modern library science, and around this key conception a series of basic conceptions are derived, we should examine again the constitutive relations between the library and the society through the variation of the key conception of the library science.

After the fading of the heat of Newman study,based on Newman s The Idea of a University,this paper makes a structural analysis of his idea with the approach of text analysis,and sorts out six core concepts in this book,namely,truth,moral,reason,general knowledge,liberal knowledge and liberal education.

This essay also gave a account to the core concepts of the harmonized socialist society such as richness,equality and sustainable d.