1. A method of information retrieval comprising: obtaining a content of a content block; representing the content as a content vector; receiving a query; representing the query as a query vector; determining a hierarchical sliding similarity and dissimilarity for matching the content vector and the query vector, and wherein determining a hierarchical sliding similarity for matching the content vector and the query vector: determining a similarity measure and a dissimilarity measure for each content vector element with respect to the query vector, wherein each content vector element is provided a unique sub-similarity similarity measure and a unique sub-dissimilarity measure; for each unique sub-similarity similarity measure and each unique sub-dissimilarity measure of each content vector element, identifying a strong match over a sliding window of sub-terms of each content vector element, wherein the strong match comprises a strong similarity match and a strong dissimilarity match; computing a sub-similarity score and a sub-dissimilarity score for each level of the convent vector element; determining a final similarity score as a combination of the strong match of some sub-vectors at different levels; and determining a final dissimilarity score as a combination of the strong match of some sub-vectors at different levels.