My research is to investigate the best ways of dealing with sexual harassment at workplace and the sample universe is female journalists in electronic media. Which theory best suits the topic?
You might explore Dougherty et al.'s study (http://www.tandfonline.com/doi/abs/10.1080/03637750802378799#.UykfuIVSud4) on language convergence/meaning divergence. It develops a communication theory that looks at sexual harassment in the workplace. Joann Keyton also does some interesting work on sexual harassment that comes out of the communication discipline. See, for instance, her piece about cultural indicators of sexual harassment (http://www.tandfonline.com/doi/abs/10.1080/10417940109373217#.Uykf8YVSud4).
There are a number of possibilities. Most communication scholars agree that communication is a discursive phenomenon. As a result, I would encourage you to consider interpretive/critical theories such as Language Convergence/Meaning Divergence (which Jimmy Manning lists in the previous comment), Weick's theory of sensemaking, or narrative theory. I would also encourage you to think beyond just the targets and perpetrators of harassment. Also consider the social environment that normalizes this kind of behavior. You are engaging an important topic and I encourage you to continue with your work.