Both DEEP ji and mazemyan are right. Fully propotional means sharing the seats on the basis of proportion of the votes each party gets. Fully proportional voting system has been adopted by few countries like The Netherlands and South Africa.

Proportional representation (sometimes referred to as full representation, or PR), is a category of electoralformula aiming at a close match between the percentage of votes that groups of candidates (grouped by a certain measure) obtain in elections and the percentage of seats they receive (usually in legislativeassemblies). It is often contrasted to pluralityvoting systems, where disproportional seat distribution results from the division of voters into multiple electoral districts, especially "winner takes all" plurality (FPTP)districts.(http://en.wikipedia.org/wiki/Proportional_representation)

Mostof the demoractic ( socilist) countries in Europe adopted mixed type of election where as world's largest democratic country India's election is based on direct elction. In the mixed type of represntation, half of the total memebers will be elected by direct election and half will be from proportional representation system. Maoist party is demanding the fully proportional election because of two main reasons.

1.  afraid of not being elected from any constituency.

2.  current history of  fully proportional system shows in majority of cases non of the party got more than 50% votes. That means there will be always hung parliament where the maoist will be able to bargain more than they deserve.