As Audrey so succinctly notes in the comments, (and as Mico and I commented on your question) you simply can't use .bst files with biblatex. So the best solution would be to find existing biblatex style that comes close to the elsarticle-harv style.
Since the elsarticle-harv is a generic author-year style, the first place to start might be one of the standard author-year styles that biblatex provides. If they are not sufficient, perhaps you could try the apa style for biblatex. This produces fairly standard Author-Year citations and bibliography. Here's a simple example with references per chapter added to the table of contents.
\documentclass{book}
% The next 4 lines are required for the biblatex-apa style
% adding the refsection=chapter option makes allows each chapter to have a
% references section
\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=apa,backend=biber,refsection=chapter]{biblatex}
\DeclareLanguageMapping{american}{american-apa}
% load your bib file (.bib suffix required)
\addbibresource{newmainjournals.bib}
\begin{document}
\frontmatter
\tableofcontents
\mainmatter
\chapter{First Chapter}
% insert some citation commands in your text
% at the end of the chapter, print the bibliography as a section, added to TOC
\printbibliography[heading=subbibintoc]
% now repeat for the next chapter
\chapter{Second Chapter}
% some more citation commands
% and the next references section
\printbibliography[heading=subbibintoc]
\backmatter
\end{document}
.bstfile :( – KOF Feb 6 at 1:19elsarticle-harvif I usebiblatexinstead ofBibTeX"? – Mico Feb 6 at 1:20natbib/elsarticle-harv/BibTeXto an alternative solution based on bibLaTeX? – Mico Feb 6 at 1:22.bstfile is a style specified in the\usepackage[style=<a-biblatex-style>]{biblatex}command. There is no one-to-one correspondence between existingnatbibstyles andbiblatexstyles, but there are a lot of harvard like styles forbiblatex. A lot depends on how exactly you need to use theelsarticle-harvstyle. – Alan Munn Feb 6 at 1:41