The Hazzan recites a special Kaddish after the Amida (or the repetition of the Amida) known as Kaddish Titkabal. Following the basic Kaddish text (which ends with "Da'amiran Be'alma"), the Hazzan adds a request that the congregation's prayers should be accepted along with those of the entire Jewish Nation: "Titkabal Selotana U'ba'utana Im Selot'hon U'ba'ut'hon De'chol Bet Yisrael…"
The Hazzan mentions the prayers of the entire nation in fulfillment of the Gemara's teaching in Masechet Berachot (30a) that when a person prays, he should pray not as a lone individual, but rather as part of the entire nation. A person himself may not be worthy of having his prayers accepted, but when he joins with all Am Yisrael, he accesses the collective merit of the nation, including the merits of the great Sadikim, and this helps ensure the acceptance of his prayers. We therefore ask not only that G-d accept our prayers, but also that He accept the prayers of the entire Jewish Nation.
We can perhaps gain further insight into the expression "Selotana U'ba'utana" – literally, "our prayers and our requests" – from the Targum Onkelos translation to a verse in Parashat Vayehi (Bereshit 48:22). Yaakob Abinu recalls how he seized the city of Shechem from his enemies "Be'harbi U'b'kashti" – "with my sword and with my bow." Targum Onkelos, interestingly enough, translates these words as "Bi'sloti U'b'ba'uti" – "with my prayer and with my request." It was clear to Yaakob that although he waged war, his success in vanquishing the enemy resulted not from his weapons, but rather from his prayers to G-d. It is also significant that Yaakob viewed Tefila as his "ammunition," as the weapons with which he defeated those who threatened him. Exploring Oneklos' translation more closely, the "sword" and the "bow" are used here as metaphors for two kinds of prayer – "Seloti" and "Ba'uti." The commentators explain that whereas a sword is used in close combat, when the enemy is right in front of the soldier, the bow is used to target enemies stationed at a distance. Correspondingly, then, "Selotana" and "Ba'utana refer to two different kinds of Tefila. Sometimes we pray like a sword – to address an immediate need, such in the case of an illness. Other times, however, we pray in the form of a bow – beseeching G-d to protect us from distant threat, from future dangers. When the Hazzan recites, "Titkabal Selotana U'ba'utana," he asks that all our prayers should be mercifully accepted – our prayers for our immediate needs, as well as our prayers for the future.