I wanted to do desertation so I need a topic of human resources management... anybody help me.:o

You should do a dissertation on why people don't take you seriously if you spell things wrong. For real. It'd be really amazing.

Oh, just use spell checker and a dictionary.

I'd do a dissertation on employee retention.

For instance, an older, experienced person is often passed up for hire in favor of younger people who can be paid a lower starting wage. Which (older versus younger) stays at the job longer (years,) calls in sick less and needs less training? Usually the older person is the better financial risk in the long run. Hiring is an expensive thing. Retention is a longstanding issue with many companies.