Google is a powerful search engine. But the results list can be endlessly long and at page 3 you still haven't found what you were looking for. These tips and tricks will help you specify a better search question.
Use unique, specific terms (keywords, not sentences). E.g. search for "headache" ...
Do you need to write a text or do you need to find information and you are looking for the right resources?
Step 1: define your subject
Narrow down your subject on the basis of literature on the subject.
Explore the subject. You can read a paper of your teacher/promotor, ...
How do I formulate my research question and how do I formulate selection criteria?
Formulate a research question in which, if possible, all aspects of your topic are named. The PICO model is a tool for setting up a clinical research question. In this model the patient category (Population/Patient), ...