If the product you are looking for is part of a particular product category, similar products will be displayed. Hence, products such as Bombesin (8-14) and (Lys3)-Bombesin will also be listed when searching for Bombesin. 
The product page includes the product name, product number, sequence, synonyms, a product description, literature references, and more. All of this information is searched for in your entry. Hence the entries containing the search term in their name will not necessarily show up first.