How to show only the bibliography which is cited

Most probably you have \nocite{*} somewhere in the body of your document; this command will cause all entries of the chosen bibliographical database to be included in the list of references.

Simply delete \nocite{*} and re-compile your document (using, for example, pdflatex+bibtex+pdflatex+pdflatex).

The \nocite command can also be used with a key-list as its argument; in this case, it will write the bibliographical information associated to the key-list (even if the publication(s) is(are) otherwise not cited) into the list of references.

@SoftTimur you must make sure that you are searching for \nocite{*} and NOT for \notice{*} this is a little late, but you consistently misspelled the command here ... so maybe you have \nocite in your document and are searching for \notice (which does not exist - is not a normal command).