If you start with a complicated search, you will probably retrieve a very small number of articles.
You are much better off to start with a general search and then refine your search from there. For example, if you are researching various aspects of the subject of plagiarism, start with a simple search just on the term plagiarism. Enter this one concept and analyze results.
Then ask yourself the following questions: how much information is available on my topic? are there better terms that I could be using? will I need to narrow or expand my topic?