System and method for top-k searching using parallel processing

Methods, systems, and programming for retrieving content items for a search are described herein. In a non-limiting embodiment, a query including a plurality of terms may be received. For each of the plurality of terms, a posting list of one or more content items may be obtained. The posting list may include a ranked list of term scores corresponding to the one or more content items, each of the term scores being indicative of a level of relevance of a corresponding content item to a term associated with the posting list. A list of relevant content items for the query may be determined based on the term scores in each posting list for the one or more content items identified with respect to each term. At least one of the relevant content items may be provided as a response to the query.