in semantic study, there are types of clause, include full statement clause, question clauses, gerund clauses, etc... i think, full statement clause is a clause as a statement. a statement clause embadded in a sentence.

Hi Qonia, I'm not exactly sure, but it could be referring to a declarative clause which functions as a statement - 'I will help you' or 'my name is Qonia' - as compared with other types of clauses, such as an interrogative clause, which functions as a question - Can you help me? or What is your name? There are others, just do a search on 'English clause types'. The 'full' could be referring to an independent clause - one that can stand alone 'I will help you', rather than a dependent clause 'because my name is Qonia'. Did you read this in a book? If so, perhaps you could post the paragraph, rather than just the sentence. Hope this helps.