Use quotation marks("") to search for exact phrase or group of words
e.g. "breakbone fever"
Use "OR" to get either results
Placing "OR" in between your keywords gives you more results
e.g. dengue OR "breakbone fever"
Use "NOT" to exclude words
e.g. health care service NOT in manila
Gadjah Mada University (Universitas Gadjah M)