When searching to add ingredients to recipes, the search defaults to “only show items I’ve ordered previously”. The search is currently limited to the past 4 weeks. (We're working to get that window lengthened.) 

To view all items available to you in the Sysco product guide, you can uncheck the box.

QUICK TIP:  if you enter a "space bar" space in the "search by... field" and click the green magnifying glass, all the items you've purchased in the last 4 weeks will pop up. (unless you turned off the default check box for previously purchased items.)