By Janet Wan
When you are sick, it is usually a good idea to search for relevant health information online before you see your doctor. In this way, you can become prepared by knowing in advance both the related medical terminology and the questions that your doctor may ask during your office visit. Nevertheless, this is often a difficult task if you use traditional keyword-based search engines.
For instance, in order to have a rough idea which diseases you are having, both the presence and the absence of certain symptoms can provide important clues (e.g., whether sputum is accompanied by coughing). However, it is challenging to describe the absence of a symptom in a way that traditional keyword-based search engines can understand.