A glance through college newspapers or free weeklies reeals classified ads promoting studies on eerything from HI accine trials to cocaine addiction to restless legs and seere PMS.

• 看看大学学报或免费周刊，你就会发现好多招聘受试者的广告，从HI疫苗实验到可卡因成瘾，不宁腿到严重的绝经后综合症。