The search textbox has an autosuggest feature. When you enter three or more characters, a list of up to 10 suggestions will popup under the textbox. Use the arrow keys to move through the suggestions. To select a suggestion, hit the enter key. Using the escape key closes the listbox and puts you back at the textbox. The radio buttons allow you to toggle between having all search items start with or contain the text you entered in the search box.
mainstream smoke (MAYN-streem ...)
Tobacco smoke that is exhaled by smokers. Mainstream smoke can be a form of secondhand smoke. It contains nicotine and many harmful, cancer-causing chemicals. Inhaling mainstream smoke increases the risk of lung cancer and may increase the risk of other types of cancer. Inhaling it also increases the risk of other health problems, such as heart disease and lung disease.