Researching Maryland legislative history is treated in depth by Chapter 5 of this guide.
Laws of Maryland (Md. Laws) (Maryland Department of Legislative Reference)
A chronological arrangement published since 1800 of the full text of all public general and public local laws passed by the Maryland General Assembly. Public General Laws are laws passed by the General Assembly that affect the entire state. Public Local Laws are laws passed by the General Assembly that only affect an area within prescribed territorial limits, for example Baltimore County. Laws for each year are organized by chapter number. There is an annual Index by subject and code section. There is also a microfiche version that covers 1979 to the present.
Lexis contains the full text of Maryland session laws from 1989 through the current legislative session. The file is updated continuously as the session proceeds.
Westlaw has laws passed during the current legislative session as well as Maryland laws from 1990.
On the internet, the Maryland General Assembly Web Site http://mgaleg.maryland.gov/webmga/frm1st.aspx?tab=home has laws enacted during the current legislative session.