Is there a way to separate full-length contigs of a assembled transcriptome from other contigs?

Question

[seta]

Dear all,

I would like to merge several assemblies resulted different K-mer, but I prefer to separate probable full-length contigs from other contigs (merging full-length contigs would not be our desired!). I did de novo assembly using CLC genomic software and assess full-length transcript using the inserted tool in the Trinity package. Now, I want to merge all contigs of different k-mer, but not full length ones. Please help me out how to extract full-length contigs? Thanks in advance