Never put an entire topic sentence into a search bar. Instead, pick out only the main keywords. For example, if my topic is "What role does administration play in urban planning?", I would choose only the words administration, urban, and planning. In my search bar it would look like:
administration urban planning
If you have trouble coming up with the important keywords, you can ask yourself the 5 Ws. Try to answer in just one or two words and use those as your keywords for searching your topic.
Who do I want to know about? Or who is involved in this topic? (could be a single person, a position, or a group)
What is this really about? What is the most important piece? (the main idea!)
Where is this taking place? (could be a geographic location, an institution, or a grouped area)
Why is this important? (think about impact of research)
When is my timeline? (while this can be a keyword, you'll more likely use a provided date limiter)
Never start a search with more than 2-3 keywords. The more keywords, the fewer the results. So start broad and then narrow in if needed.