The paper presents the results of the analysis of the difficulties evidenced by the students while approaching some scientific disciplines (the ones the author has been teaching or involved with) and shows various kinds of these problems usually known as preconceptions, misconceptions or mental schemes in students' learning.

The work describes then the strategies adopted to help students in overcoming their difficulties by using specific strategies built up with the help of the constructivistic paradigm. It analyzes soon after the experiences made by the author while using Web techniques to support his teaching activity and proposes the model of a special Web site where e-commerce techniques have been adopted.

The paper ends with the description of the monitoring process of students' knowledge one can carry out with the above site by using the Data Base it's interfaced with and gives an outline of the possible knowledge paradigms this instrument leads to.