Search by exact form

A one word search (for example, отечества) yields all contexts, which contain the exact form of the word (but not отечеством, отечеств, &c.). A search for several words (И дым отечества нам сладок и приятен) yields all contexts, which contain the wordforms within one sentence, not necessarily in the order of the search (for example, Отечества и дым нам сладок и приятен will also be suggested)